The answer is 83. 83+5=88. just subtract it.
688
x 29
6192
1376 x
19952
So you start by taking 9 from 29 and multiplying it by 688. when you get the answer put it below the line. then multiply the 2 from the 29 and whne you get the answer put a zero on the end and then add the answer you got from 9x688 (6192) and 2x688 (13760) and then thats youre answer. hope it helps!
B= 30
a2+b2=c2
72^2+b^2 = 78^2
5184+b^2 = 6084
b2 = 900
b = 30