What are vertically opposite angles, and what is true of them?

They are the pairs of angles facing each other where two straight lines cross. Vertically opposite angles are always equal .

True or False? When two straight lines cross, all four of the angles formed are equal.

False. Only the pairs facing each other are equal. Angles that sit next to each other are on a straight line, so they add to 180° instead, and they are equal only in the special case where every angle is 90°.

What do the three interior angles of any triangle add up to?

They always add up to 180°. This holds for every triangle, whatever its shape or size.

In an isosceles triangle, which two angles are the equal ones?

The two angles opposite the two sides of equal length . It is the position relative to the equal sides that decides it, not where the triangle happens to be drawn on the page.

True or False? A right-angled triangle can also be isosceles.

True. A triangle with angles of 90°, 45° and 45° is both. The names describe different things, one the presence of a right angle and the other a pair of equal sides, so a triangle can satisfy both at once.

What do the four interior angles of any quadrilateral add up to?

They always add up to 360° . This holds for every quadrilateral, however irregular its shape.

What is true of every angle in a square or a rectangle ?

Every one of the four angles is a right angle, 90° . Four lots of 90° make the 360° that any quadrilateral must total.

In a parallelogram or a rhombus , which angles are equal?

The opposite angles are equal, giving two pairs of equal angles. The angles next to each other are not equal unless the shape happens to be a rectangle or a square.

How many pairs of equal opposite angles does a kite have?

Just one pair. The two angles between the pairs of equal sides are the equal ones, and the other two angles are generally different from each other.

True or False? Every quadrilateral has at least one pair of equal angles.

False. An irregular quadrilateral can have four angles that are all different from one another. Equal angles come from a shape's symmetry, and an irregular quadrilateral has none.

True or False? The sum of the exterior angles in any polygon always adds up to 360° .

True. The sum of the exterior angles in any polygon always adds up to 360° .

True or False? The sum of an interior angle and an exterior angle at the same vertex on a polygon is equal to 180° .

True. The sum of an interior angle and an exterior angle at the same vertex on a polygon is equal to 180° .

What is a regular polygon ?

A regular polygon is a polygon where all sides are equal and all angles are equal .

True or False? An irregular polygon can have more than one side of the same length .

True. An irregular polygon can have more than one side of the same length . It is an irregular polygon unless all sides are the same length and all angles are the same size, in which case it would be a regular polygon.

True or False? The sum of interior angles in a regular polygon is different to the sum of interior angles in an irregular polygon with the same number of sides.

False. The sum of interior angles in a regular polygon is the same as the sum of interior angles in an irregular polygon with the same number of sides. The sum of interior angles is dependent on the number of sides . It is not dependent on whether the polygon is regular or irregular.

What are parallel lines ?

Parallel lines are lines that are always equidistant (i.e. the same distance apart) and never meet .

What is a transverse line ?

A transverse line is a straight line that extends across two parallel lines .

True or False? In an exam question involving the use of angle facts, you should state the appropriate angle fact as well as the size of the relevant angle .

True. To get full marks in an exam you will need to write down the size of any angles that you have found but you will also need to give reasons . Make sure that you use the correct terminology for the different angle facts.

GCSEMathsEdexcelFoundationFlashcardsGeometry & MeasuresAngles in Polygons & Parallel Lines

Angles in Polygons & Parallel Lines (Edexcel GCSE Maths: Foundation): Flashcards

Exam code: 1MA1

1/29

0Still learning

Know0

FrontAngles around Points & Lines
Complete the two basic angle facts by filling in the missing numbers:
Angles around a point add up to $______$ °.
Angles on a straight line add up to $______$ °.

Was this flashcard helpful?

Cards in this collection (29)

Complete the two basic angle facts by filling in the missing numbers:
Angles around a point add up to $______$ °.
Angles on a straight line add up to $______$ °.
The completed facts are:
Angles around a point add up to 360°.
Angles on a straight line add up to 180°.
What are vertically opposite angles, and what is true of them?
They are the pairs of angles facing each other where two straight lines cross.
Vertically opposite angles are always equal.
Two of the angles on a straight line are 25° and 98°. What is the third angle on that line?
The third angle is 57°.
The three angles must total 180°, and $180 - 25 - 98 = 57$ .
Three angles meet around a point. Two of them are 120° and 95°. What is the third?
The third angle is 145°.
Angles around a point total 360°, and $360 - 120 - 95 = 145$ .
True or False?
When two straight lines cross, all four of the angles formed are equal.
False.
Only the pairs facing each other are equal.
Angles that sit next to each other are on a straight line, so they add to 180° instead, and they are equal only in the special case where every angle is 90°.
What do the three interior angles of any triangle add up to?
They always add up to 180°.
This holds for every triangle, whatever its shape or size.
In an isosceles triangle, which two angles are the equal ones?
The two angles opposite the two sides of equal length.
It is the position relative to the equal sides that decides it, not where the triangle happens to be drawn on the page.
Complete the two angle facts by filling in the missing numbers:
Every angle in an equilateral triangle is $______$ °.
A right-angled triangle has one angle of $______$ °.
The completed facts are:
Every angle in an equilateral triangle is 60°.
A right-angled triangle has one angle of 90°.
In an equilateral triangle all three angles are equal, so each one is $180 \div 3$ .
True or False?
A right-angled triangle can also be isosceles.
True.
A triangle with angles of 90°, 45° and 45° is both.
The names describe different things, one the presence of a right angle and the other a pair of equal sides, so a triangle can satisfy both at once.
An isosceles triangle has two angles of 70°. What is its third angle?
The third angle is 40°.
The three angles total 180°, so the remaining angle is $180 - 70 - 70 = 40$ .
What do the four interior angles of any quadrilateral add up to?
They always add up to 360°.
This holds for every quadrilateral, however irregular its shape.
What is true of every angle in a square or a rectangle?
Every one of the four angles is a right angle, 90°.
Four lots of 90° make the 360° that any quadrilateral must total.
In a parallelogram or a rhombus, which angles are equal?
The opposite angles are equal, giving two pairs of equal angles.
The angles next to each other are not equal unless the shape happens to be a rectangle or a square.
How many pairs of equal opposite angles does a kite have?
Just one pair.
The two angles between the pairs of equal sides are the equal ones, and the other two angles are generally different from each other.
Three angles of a quadrilateral are 97°, 115° and 85°. Complete the working for the fourth:
$360 -______=______$ °
The completed working is:
$360 - 297 = 63$ °
The three given angles total $97 + 115 + 85 = 297$ .
True or False?
Every quadrilateral has at least one pair of equal angles.
False.
An irregular quadrilateral can have four angles that are all different from one another.
Equal angles come from a shape's symmetry, and an irregular quadrilateral has none.
What is a polygon?
A polygon is a flat (plane) shape with $n$ straight sides.
E.g. a quadrilateral is a 4-sided polygon.
True or False?
The sum of the exterior angles in any polygon always adds up to 360°.
True.
The sum of the exterior angles in any polygon always adds up to 360°.
True or False?
The sum of an interior angle and an exterior angle at the same vertex on a polygon is equal to 180°.
True.
The sum of an interior angle and an exterior angle at the same vertex on a polygon is equal to 180°.
State the equation in terms of the number of sides of a polygon, $n$ , for the sum of interior angles in a polygon.
The equation in terms of the number of sides of a polygon, $n$ , for the sum of interior angles in a polygon is:
Sum of interior angles = $180 \times (n - 2)$ .
What is a regular polygon?
A regular polygon is a polygon where all sides are equal and all angles are equal.
True or False?
An irregular polygon can have more than one side of the same length.
True.
An irregular polygon can have more than one side of the same length.
It is an irregular polygon unless all sides are the same length and all angles are the same size, in which case it would be a regular polygon.
True or False?
The sum of interior angles in a regular polygon is different to the sum of interior angles in an irregular polygon with the same number of sides.
False.
The sum of interior angles in a regular polygon is the same as the sum of interior angles in an irregular polygon with the same number of sides.
The sum of interior angles is dependent on the number of sides.
It is not dependent on whether the polygon is regular or irregular.
What are parallel lines?
Parallel lines are lines that are always equidistant (i.e. the same distance apart) and never meet.
What is a transverse line?
A transverse line is a straight line that extends across two parallel lines.
What are corresponding angles?
Corresponding angles are equal angles in corresponding positions.
What are co-interior (supplementary) angles?
Co-interior (supplementary) angles are a pair of angles that are formed between a pair of parallel lines and a transverse line. Co-interior angles sum to 180^o.
What angle fact is represented by the diagram below?
Alternate angles are equal angles.
True or False?
In an exam question involving the use of angle facts, you should state the appropriate angle fact as well as the size of the relevant angle.
True.
To get full marks in an exam you will need to write down the size of any angles that you have found but you will also need to give reasons.
Make sure that you use the correct terminology for the different angle facts.

Sign up to unlock flashcards

By signing up you agree to our Terms and Privacy Policy

Previous:Symmetry & ShapesNext:2D & 3D Shapes