# A boy

A boy of height 1.7m is standing 30m away from flag staff on the same level ground . He observes that the angle of deviation of the top of flag staff is 30 degree. Calculate the height of flag staff.

Result

h =  19.021 m

#### Solution:

$a=30 \ \text{m} \ \\ b=1.7 \ \text{m} \ \\ A=30 \ ^\circ \ \\ \ \\ \tan A=x/a \ \\ \ \\ h=b + a \cdot \ \tan( A ^\circ \rightarrow\ \text{rad} )=b + a \cdot \ \tan( A ^\circ \cdot \ \dfrac{ \pi }{ 180 } \ )=1.7 + 30 \cdot \ \tan( 30 ^\circ \cdot \ \dfrac{ 3.1415926 }{ 180 } \ )=19.02051=19.021 \ \text{m}$

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