Question

the measure of c is...?

Answer 1

c - is a hypotenuse,
so we can use Pythagorean theorem. 
c² =a² +b² 
c² = 8²+12²=64 + 144 = 16*4 +16*9=16(4+9) =16*13
c²=16*13
c=√(16*13)=√16*√13=4√13
c=4√13
Answer C. 4√13