Posted by **Cas'** on Sunday, January 16, 2011 at 2:33am.

When the sun's angle of elevation is 30 degree the shadow of a post is 6 ft longer than when the angle is 45

degree. find the height of the post

- trig -
**Reiny**, Sunday, January 16, 2011 at 8:41am
let the height of the post be h ft, let the length of the shadow be x

when angle is 45°, the height of the post and its shadow would be equal, so x = h at 45°

at 30°, length of shadow = h+6

tan 30 = h/(h+6)

1/√3 = h/(h+6)

√3h = h + 6

√3h - h = 6

h(√3 - 1) = 6

h = 6/(√3 - 1) = appr. 8.2 ft

√3h - h =

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