Answer:
17
18 1.404 m
Explanation:
17
The cosine of an angle for a right triangle is the length of the adjacent side divided by the hypotenuse.
See figure for graphic view relating to this calculation
Here we can see that the hypotenuse if l, the adjacent side to the angle θ is l-h so we get
cosθ = (l-h)/l
Multiplying both sides by l gives
lcosθ = l-h ==> h = l - lcosθ which simplifies to h = l(1-cosθ)
Q 18
For θ = 40°, cosθ = 0.766
h = 6(1-0.766) = 6(0.234) = 1.404 m