The answer would be 31 in.
First do the Pythagorean theorem.
225+ 729= 954
Then find the square root of 954 which is 30.88 repeating, so round up to 31 in.
The probability of matching the first one correctly is 1/3 .
Then there are only two baby-pix left, so ...
The probability of matching the second one correctly is 1/2 .
Then there's only one baby-pic left, so ...
The probability of matching the third one correctly is 1 .
So the probability of matching all three correctly is
(1/3) x (1/2) x (1) = 1/6 = (16 and 2/3) percent .
I think it may be 5+3 and carry the one up top to get the sum of 56.
