Question

A triangular patch of grass in a park is bordered by walking paths. The longest path bordering the patch of grass measures 110 feet. The smallest path bordering the patch of grass measures 55 feet. The smallest angle formed by the paths bordering the patch of grass measures 29º.

What is the measure of the largest angle of the triangular patch of grass? Round your answer to the nearest
degree. Show all your work.

Answer 1

76 degrees

Explanation:

First, we can draw a picture. Two of the sides are 110 feet and 55 feet. In a triangle, the smallest angle is opposite the smallest side and vice versa. Therefore, if I have my triangle arranged in the way shown, the smallest angle of 29 degrees will be opposite of the smallest side of 55 feet.

The law of sines states that a/sinA=b/sinB=c/sinC , with corresponding angles being opposite of its corresponding side. Therefore, we can say that

55 feet/ sin(29 degrees) = 110 / sin(largest angle).

If we say that the largest angle is equal to x, we can say

55 / sin(29°) = 110/sin(x)

multiply both sides by x to remove a denominator

55 * sin(x)/ sin(29°) = 110

multiply both sides by sin(29°) to remove the other denominator

55 * sin(x) = 110 * sin(29°)

divide both sides by 55 to isolate the sin(x)

sin(x) = 110 * sin(29°) / 55

For an angle, if sin(x) = y, we can say that arcsin(y) = x. Therefore, we can say

x = arcsin(110 * sin(29°)/55)

x ≈ 76 degrees