Question

Work out the length x in the triangle below.

If your answer is a decimal, give it to 1 d.p.
area = 60 m²
15 m
x
30°

Answer 1

x = 16 m

Explanation:

given a trianglewith 2 sides and the included angle , then area (A) is calculated as

A =
`(1)/(2)` ab sin C

a, b are the 2 known sides and C the angle between them

here a = 15 , b = x and C = 30°

given A = 60 , then

60 =
`(1)/(2)` × 15 × x × sin30° [ sin 30° = 0.5 ]

60 = 7.5x × 0.5 = 3.75x ( divide both sides by 3.75 )

16 = x