Hello there!
Here, we want to use the Pythagorean Theorem:
.
For problem number 7, we plug 6 and 8 in for a and b. Like this:
Now we solve.
is 36.
is 64.
64 + 36 = 100
Then, we take the square root of 100 to get c.
(There's something special about this triangle. If you want I'll tell you about it in the comments.)
For problem number 8, we do the same exact thing.
and
I hope this helps!!