Answer:
1) b= 39.5
2) c= 3.6
3) a=19
Step-by-step explanation:
Use the Pythagorean Theorem to find the missing side length.
"C" is the hypotenuse. Pythagorean Theorem: a^2+b^2=c^2
1) 11^2+b^2=c^41
121+b^2=1681
121-121+b^2=1681-121
b^2=1560
b= 39.5
2) 2^2+3^2=c^2
4+9=c^2
13=c^2
c= 3.6
3) a^2+9^2=21^2
a^2+81=441
a^2+81-81=441-81
a^2=360
a=19
Hope this helps!