Question

If the shadow of a building increases by 10 meters when the angle of elevation of the sun rays decreases from 70o to 60o, what is the height of the building?

Answer 1

Make two right-angled triangles,
let the base (length of shadow) of the first be x, and its base angle is 70°
let the base of the second be x+10, and label its base angle as 60°
For both let the height (the building) be h
from the first:
tan70 = h/x ---> h = xtan70
from the second:
tan60 = h/(x+10) ---> h = (x+10)tan60

then xtan70 = (x+10)tan60
xtan70 = xtan60 + 10tan60
xtan70 - xtan60 = 10tan60
x(tan70-tan60) = 10tan60
x = 10tan60/(tan70-tan60)

back in h = xtan70
h = 10tan60tan70/(tan70-tan60)
= appr 46.9 m

Answer 2

i im a maek a wish child, nd i hve bin working on dis problim 4 too dayz

Answer 3

987

Answer 4

You need to work on both triangles that you have created, seeing as there are two unknowns. Then you have to write one equation as a function of another and plug that in. After this, it's just basic problem-solving.

The answer (rounded) = 46.86

But you may get a different answer, depending on whether you calculate the tangents at the beginning or end on the exercise.

Answer 5

4.3432