Answer:
b = square root of 125
Put into calculator and put to 1dp
Explanation:
Pythagorean theorem is
a^2 + b^2 = c^2
The a and b are the two short sides and c is always the hypotenuse
We just put the numbers in
10^2 + b^2 = 15^2
Now we can rearrange so that b^2 is by its self on the left side
b^2 = 15^2 - 10^2
Now just solve by putting into calculator
b^2 = 125
And finally square root to get b^2 down to b
b = square root of 125
Put into calculator and put to 1dp