Answer:
Step-by-step explanation:
So basically you have to do the Pythagorean Theorem here. 
Which is =  a^2 + b^2 = c^2 
So you'll put 35 in 'a' and 84 in 'b'
It'll be like this = 35^2 + 84^2 = c^2
So here, we are looking for 'c'
And 'c' is the hypotenuse 
So,
Step 1: 35^2 + 84^2 = c^2
Step 2: You will use the exponents (but not for c) 
=  1225 + 7056 = c^2
Step 3: You will now add 1225 + 7056 = 8281
Step 4: Now, square root 8281√8281 = 91 
91 = c
Hope this helps! Please let me know if you get this correct!