Answer:
36 units
Explanation:
there is 12 units at is base and 9 as its height
you have to use the Pythagorean theorem to find the hypotenuse
c= √(a^2+b^2)( be being 12 and a 9)
plug it in and get c=√(81+144)=√225=15
perimeter is a+b+c
now that we have c do 12+15+9
=36