Question

a = \frac{1}{2}bh
what are the actual base and height of the trampoline?
actual base = ft
actual height = ft
1 in. : 4 ft

Explanation:

Step1: Find actual base

Use scale factor. Given scale 1 in. : 4 ft and base on drawing is 2.5 in.
$2.5\times4 = 10$

Step2: Find actual height

Given height on drawing is 3 in. Use scale factor.
$3\times4=12$

Answer:

Actual base = 10 ft
Actual height = 12 ft