Answer: x=12dm
Step-by-step explanation:
c=13 means hypotenous
a=5 means altitude
b=x=? means base
By pythagorean theorem
c^2=a^2+b^2
(13)^2=(5)^2+(x)^2
169=25+x^2
x^2=169-25
x^2=144
Taking sqrt on both sides
x=12
