Heights and Distances Practice Test 1

Question : 18 of 40

Marks: +1, -0

From the top and bottom of a building of theangles of elevation of the top of a tower, i.e.,30 m are 30° and 45° respectively. Find theheight of the building?

${30√3}/{√3-1}$
${30√3}/{√3+1}$
${30 }/{√3-1}$
All of the above
None of these

Validate

Solution:

In ΔEDA,

h/x=\tan30°=1/√3

√3h=x

......(1)
In ΔECB,

{h+30}/x=\tan 45°=1

h+30=x

...... (2)
From equations (1) and (2)

√3h=h+30

h=30/{√3-1}

Height of the building

= h + 30 = 30/{√3-1}+30={30√3}/{√3-1}

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