Pythagorean Theorem
a² + b² = c²
c = 13
a = 4
(Missing side) = b
4² + b² = 13²
16 + b² = 169
16 - 16
169 - 16 = 153
Square Root of 153 = 12.369
b = 12.369
The missing side is 12.369 (rounded to 12 as a whole number)
The answer is 0.1 lbs. Or 1/10 lbs.
Hope this helps!
If you add up all of the money he made and divide it by the amount he made via tips, you will see that the percent tip he received was 16%
