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Problem # 1. A scarecrow was built in the middle of a cornfield.
A naughty crow and seemingly brave crow landed on top of the scarecrow and upon being seen by the farmer,
the crow was chased away. As a result, the scarecrow is slightly tilted toward the sun
at an angle of 12° from the vertical and casts a 3-meter shadow. The angle of elevation
from the tip of the shadow to the top of the scarecrow is 27°.
Determine the length of the scarecrow.
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The problem in the post by tutor @yurtman is solved incorrectly.
I came to bring a correct solution.
I will solve here first part, only, for determining the length of the scarecrow.
We have a triangle ABC.
Vertex A is the base of the scarecrow.
Vertex B is the tip of the shadow on the ground.
The side AB is horizontal on the ground. It represents the shadow on the ground and its length is 3 meters.
Point C is the top of the scarecrow.
Angle B is 27° : it is the angle of elevation from the tip of the shadow to the top of the scarecrow.
Side AC makes the angle of 12° with vertical toward the sun;
so the angle A is 90° + 12° = 102°.
They want we find the length AC, which is the length of the scarecrow.
First, calculate the angle C of the triangle as the third angle of the triangle ABC
m(C) = 180° - 102° - 27° = 51°.
Now write the sine law equation
=
=
AC = = = 1.753 meters.
ANSWER. The length of the scarecrow is 1.753 meters.
Solved.