Grade 6 Geometry: Area of Triangles

Worked examples

Real problems from the practice worksheets, solved one step at a time.

1. Example 1

   A triangle has a base of 18 m and a height of 2 m. What is its area in square meters?

   1. Area of a triangle = ½ × base × height (a triangle is half of a rectangle).
   2. Base × height: 18 × 2 = 36.
   3. Take half: 36 ÷ 2 = 18. The area is 18 square meters.

   Answer: 18

2. Example 2

   A triangle has an area of 36 square inches and a base of 12 in. What is its height in inches?

   1. Area = ½ × base × height, so base × height = 2 × area = 2 × 36 = 72.
   2. Divide by the base: 72 ÷ 12 = 6.
   3. Check: ½ × 12 × 6 = 36. The height is 6 inches.

   Answer: 6

3. Example 3

   A right triangle has legs of 13 in and 5 in. What is its area in square inches?

   1. In a right triangle the two legs meet at a right angle, so one leg is the base and the other is the height. Area = ½ × base × height.
   2. Base × height: 13 × 5 = 65.
   3. Take half: 65 ÷ 2 = 32.5. The area is 32.5 square inches.

   Answer: 32.5