I need help please and thank you

C=10.6

Pythageron theorem is
a^2+b^2=c^2

a and b are the legs of the triangle, in this case 8 and 7. The c is the hypotenuse, in this the unknown.

Substitute 8 and 7 in for a and b.

8^2+7^2=c^2
64+49=c^2
113=c^2
Take the square root of both sides

c=10.6301458

Rounded to the nearest tenth
c=10.6

Hope this helps! :)