Question

The formula for the area of a triangle is a=1/2bh. Hiro is solving the equation for h; his work is shown below. What mistake did Hiro make?

a=1/2bh
2(x)a=2(x)(1/2bh)
2a=bh
2a-b=h
(x) is multiplication sign btw
Hiro should have divided both sides of the equation by 2. Hiro should have divided both sides of the equation by b. Hiro should have added b to both sides of the equation. Hiro should have subtracted 2 from both sides of the equation.

Answer 1

Hiro should have divided both sides of the equation by 2.

Example

If b = 5 and h = 10

a = 1/2 * b * h

a = 1/2 * 5 * 10

a = 25

2a = 2 (1/2 * b * h)

2 * 25 = 2 (1/2 * 5 * 10)

50 = 2 (25)

50 = 50

2a = b * h

2 * 25 = 5 * 10

50 = 50

2a - b = h

2 * 25 - 5 = 10

50 - 5 = 12

45 = 10

This is false.

If Hiro divided both sides by 2 instead:

2a ÷ 2 = b * h ÷ 2

2 * 25 ÷ 2 = 5 * 10 ÷ 2

50 ÷ 2 = 50 ÷ 2

25 = 25

Answer 2

Hiro should divide both sides by 2.

Explanation: