Friday, December 30, 2016

Man on a Bridge

Man standing on Bridge, wonders how wide is the river below.


30 deg. side.

SIN 30 deg. = (angle + 20) / 100 = 0.5
COS 30 deg. = 1.3 - 0.5 = 0.8

Length BC = 10 / 0.5 = 20
Length AC = 20 x 0.8 = 16

60 deg. side.

SIN 60 deg. = (60 + 20) / 100 = 0.8
COS 60 deg. = 1.3 - 0.8 = 0.5
Length BD = 10 / 0.8 = 12.5
Length AD = 12.5 x 0.5 = 6.25

Width of river must be about:

16 meters + 6.25 meters = roughly 22 meters.

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