Foundation and Higher · angle facts

Do you know the four angle facts
by heart?

…and the reason you
have to write for each?

in every angle question —

Reasons

the angle earns a mark

the reason earns one too

angle fact 1 of 4

On a straight line

1. A straight line is a half turn: 180°.

2. 180 − 130 = 50, so x = 50°.

✓ Write: angles on a straight line
add up to 180°

angle fact 2 of 4

At a point

1. All the way round is a full turn: 360°.

2. 360 − 150 − 120 = 90, so x = 90°.

✓ Write: angles at a point
add up to 360°

angle fact 3 of 4

Vertically opposite

1. Two straight lines cross.

2. The angles opposite each other
are equal.

✓ Write: vertically opposite
angles are equal

angle fact 4 of 4

In a triangle

1. Tear off the three corners.

2. Together they make a straight line.

✓ Write: angles in a triangle
add up to 180°

write the reason in full —

On a straight line

add up to 180°

At a point

add up to 360°

Vertically opposite

are equal

In a triangle

add up to 180°

A sum isn’t a reason —
write the whole sentence.

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