Angles on parallel lines

The Maths Habit

  1. Two angles make a straight line. One is 47°. Find the other.

    133°

  2. Three angles meet at a point. Two of them are 90° and 115°. Find the third.

    155°

  3. A triangle has angles of 38° and 71°. Find the third angle.

    71°

Which angles look the same size?

a, d, e and h. Then b, c, f and g.

Corresponding
Matching positions on the two parallel lines. Equal.
Alternate
Opposite sides of the crossing line, in between. Equal.
Co-interior
Same side of the crossing line, in between. Add to 180°.

Correspondingequal

Alternateequal

Co-interioradd to 180°

Find the size of angle x. Give a reason.

x = 57°

Alternate angles are equal

x = 124°

Alternate angles are equal

x = 57°

Alternate angles are equal

x = 56°

Co-interior, add to 180°

x = 57°

Alternate angles are equal

x = 63°

Corresponding angles are equal

x = 57°

Alternate angles are equal

x = 128°

Alternate angles are equal

x = 57°

Alternate angles are equal

x = 114°

Co-interior, add to 180°

Angles on parallel lines worksheet, page 1

Angles on parallel lines worksheet, page 2

Answer sheet

  1. A parallelogram has one angle of 70°. Find its other three angles.

    110°, 70°, 110°

  2. Two co-interior angles are x and x + 40°. Find both angles.

    70° and 110°

  3. Two corresponding angles are 2x + 10° and 76°. Find x.

    33°

  1. Find angle x. Give a reason.

    x = 64°, corresponding
    64°x

  2. Find angle y. Give a reason.

    y = 118°, alternate
    118°y

  3. Find angle z. Give a reason.

    z = 109°, co-interior
    71°z
Exit tickets to print