Answer:
6.9
Step-by-step explanation:
Use the Pythagorean theorem :
a^2 + b^2 = c^2
so,
11^2 + b^2 = 13^2
121 + b^2 = 169
b^2= 48
b = 6.928
Round to the tenth : 6.9
n=12
5/6n=10
*6 *6
5n=60
its an equallateral so its 60 degrees
