Find, to the nearest unit, the length of each diagonal

Question

The length of each side of a rhombus is 12. The measure of an angle between two adjacent sides is 40. Find, to the nearest unit, the length of each diagonal

Answer 1

Hi Diamond,

 

See this picture to get the idea: 

 

https://www.desmos.com/calculator/dhmbl3yt9h

 

The d1 in the diagram represents 1/2 of one of the diagonals.

Use the cos 20 to find 1/2 of the other diagonal. 

Those results can be doubled to get the length of each diagonal.

 

There are other ways to do this problem.