Trigonometry Question

Question

It is 1.9 miles from a house to a restaurant and 1.2 miles to a pier.  The angle between the two lines of sight is 87 degrees. How far is it from the pier across the water to the restaurant?

Round to the nearest tenth

Answer 1

Using cosine theorem the distance from the pier across the water to the restaurant in miles is:

square root(1.9*1.9+1.2*1.2-2*1.2*1.9*cos(87degrees)) = 2.2 miles