Answer:
h ≈ 209 ft
Step-by-step explanation:
The illustration forms 2 right angle triangle with same height , which is the height of the pyramid.
The first triangle has an unknown adjacent side and height but the angle is 31° 10'. The larger triangle has adjacent side of 120 ft plus the adjacent side of the smaller triangle.
let
the adjacent side of the smaller triangle = a
recall both triangle have same height = h
Therefore,
tan 31° 10' = opposite/adjacent = h/a
tan 31.167 = h/a
h = a tan 31.167
h = 0.6048345941 a
The larger triangle
adjacent side = 120 + a
height = h
tan 24° 10' = h/120 + a
convert the minutes to degree
tan 24.167° = h/120 + a
cross multiply
120 + a tan 24.167 = h
120 + a (0.44872570999
) = h
h = 53.8470851998 + 0.44872570999a
Therefore,
0.6048345941 a = 53.8470851998 + 0.44872570999a
0.6048345941 a - 0.44872570999a = 53.8470851998
0.1561094942
a = 53.8470851998
divide both sides by 0.1561094942
a = 53.8470851998
/ 0.1561094942
a = 344.931520506
a ≈ 345 ft
The height can be computed as
tan 31.167 = h/a
h = 345 × tan 31.167
h = 345 × 0.6048345941
h = 208.667934967
h ≈ 209 ft
