Find the distance

Question

A surveyor on one side of a river wants to find the distance between points A and B on the opposite side of the river. On her side, she chooses C and D, which are 20m apart, and measures angles; ACB-40 degrees, BCD-20 degrees, ADC-45 degrees, and ADB-42 degrees. Find the distance.

 

I am currently studying precalculus and need help!

Answer 1

Well, it doesn't matter.

 

Draw a diagram - no need to be accurate.

Label the size of ALL angles - not just the four given.

Use the Law of Sines twice.

 

First use it to find the length of either AC or BD, doesn't matter which.

After finding that length use it in the Law of Sines for find the length of AB