Question

Given that y= 8 cm and θ= 39 °, work out x rounded to 1 decimal place. (not drawn to scale)

Answer 1

Answer:

x = 6.2

Use cosine rule:

$\sf cos(\theta) = \dfrac{adjacent}{hypotenuse}$

Inert following:

$\sf cos(39) = \dfrac{x}{8}$

change sides

$\sf x = 8cos(39)$

simplify

$\sf x = 6.2$

Answer 2

Answer:

x ≈ 6.2 cm

Step-by-step explanation:

using the cosine ratio in the right triangle

cosΘ = $\frac{adjacent}{hypotenuse}$ , that is

cos39° = $\frac{x}{y}$ = $\frac{x}{8}$ ( multiply both sides by 8 )

8 × cos39° = x , then

x ≈ 6.2 cm ( to 1 dec. place )