Answers:
In order from left to right the answers are 53, 48, and 90
Step by step:
For the first one you are solving for the hypotenuse using Pythagorean theorem
28^2 + 45^2 = c^2
784 + 2025 = c^2
2809 = c^2
Now take the square root of both sides to get
56 = c, which is the answer to number 1.
For number two you are solving for one of the legs but your still using the same formula
4096+ b^2 = 6400
Now subtract 4096 from both sides to get
b^2 = 2304, now take the square root
to get b = 48, which is your answer
Finally for the third it is the same thing as number two
Setup your equation and solve
56^2 + b^2 = 106^2
3136 + b^2 = 11236
b^2 = 8100
b = 90
Hope this helps!