Help plz ASAP , geometry

Answer:
Step-by-step explanation:
Use the Pythagorean theorem
a^2 + b^2 = c^2 where a and b are the sides and c is the hypotenuse (longest side)
a^2 + 7^2 = 8^2
a^2 + 49 = 64
a^2=15
Now take the square root of 15 which is about 3.8