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35 votes
35 votes
Given that y= 8 cm and θ= 39 °, work out x rounded to 1 decimal place.

(not drawn to scale)

Given that y= 8 cm and θ= 39 °, work out x rounded to 1 decimal place. (not drawn-example-1
User Tulkkas
by
2.9k points

2 Answers

18 votes
18 votes

Answer:

x ≈ 6.2 cm

Explanation:

using the cosine ratio in the right triangle

cosΘ =
(adjacent)/(hypotenuse) , that is

cos39° =
(x)/(y) =
(x)/(8) ( multiply both sides by 8 )

8 × cos39° = x , then

x ≈ 6.2 cm ( to 1 dec. place )

User Naveed Ali
by
2.9k points
11 votes
11 votes

Answer:

x = 6.2

Use cosine rule:


\sf cos(\theta) = (adjacent)/(hypotenuse)

Inert following:


\sf cos(39) = (x)/(8)

change sides


\sf x = 8cos(39)

simplify


\sf x = 6.2

User Bugzilla
by
3.1k points