Area of a triangle

The Maths Habit

  1. Work out the area.

    77 cm2

  2. Work out the area.

    36 m2

  3. Work out the area.

    54 cm2

Which triangle has the bigger area?

A

B

They are the same

Base
The side the shape sits on.
Perpendicular height
The height measured at a right angle to the base.

Area = ½ × base × height

Work out the area.

Work out the area.

Area = ½ × base × height
Area = ½ × 16 × 5 = 40 cm2
Answer40 cm2
Area = ½ × base × height
Area = ½ × 13 × 8 =52 cm2
Answer52 cm2
Area = ½ × base × height
Area = ½ × 16 × 5 = 40 cm2
Answer40 cm2
Area = ½ × base × height
Area = ½ × 15 × 6 = 45 cm2
Answer45 cm2
Area = ½ × base × height
Area = ½ × 16 × 5 = 40 cm2
Answer40 cm2
Area = ½ × base × height
Area = ½ × 12 × 5 = 30 cm2
Answer30 cm2
Area = ½ × base × height
Area = ½ × 16 × 5 = 40 cm2
Answer40 cm2
Area = ½ × base × height
Area = ½ × 14 × 8 = 56 m2
Answer56 m2
Area = ½ × base × height
Area = ½ × 16 × 5 = 40 cm2
Answer40 cm2
Area = ½ × base × height
Area = ½ × 9 × 5 = 22.5 cm2
Answer22.5 cm2

Area of 2D shapes worksheet, page 1

Area of 2D shapes worksheet, page 2

Answer sheet

  1. A triangle has an area of 36 cm2 and a base of 9 cm. How tall is it?

    8 cm

  2. A triangle and a rectangle have the same base and the same area. The rectangle is 5 cm tall. How tall is the triangle?

    10 cm

  3. A triangle has a base of 18 cm, a sloping side of 11 cm and a perpendicular height of 7 cm. Work out its area.

    63 cm2

Work out the area of each triangle.

A

B

Both are 20 cm2

  1. Work out the area of the triangle.

    42 cm2
    6 cm14 cm10 cm

  2. Work out the area of the triangle.

    36 cm2
    8 cm9 cm17 cm

  3. A triangle has an area of 24 cm² and a base of 8 cm. Find its perpendicular height.

    6 cm
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