exam Maths Puzzle Numerical Ability

i have to solve M5=12 i dont understand?

Read Solution (Total 0)

exam Other Question

Find the length x in each triangle. Express your answer in simplified radical form.

Side 1: 10 Side 2: 8 Bottom: x

I need some help with this problem. Thanks (Area of Plane Figures)
For a regular polygon:
S=3960
n=
a=
e=
E=
I would like to know how to get a,e, and E.