1) A
a^2+b^2 =c^2 where c is the hypotenuse
6^2+5^2=c^2
36+25=c^2
c^2=61
take square root of both side
c= √61
2) C
same concept, but now we already have c, just need to find the other leg measurements (let’s call it a but it doesn’t matter a or b is fine)
a^2+19.5^2=20^2
a^2=20.2^2-19.5^2
take square root
a= √20.2^2-19.5^2