Question

Big idea math (image)

Answer 1

DB = approximately 16

Explanation:

DEC is a right triangle => DC=10. Because all four sides are equal in a rhombus, then AD=AB=10. Then, because angle BAD is 53*2=106 degrees, we can use cosines. DB=sqrt(10^2+10^2-2*10*10cos(106deg))=15.9727102009.