Answer: 3,4,5
Step-by-step explanation: a squared + b squared = c squared
A -> 3 squared is 9
B -> 4 squared is 16
9+16 is 25, so C has to be 25
C -> 5 squared is 25
So 3, 4, 5
From the setup of the problem, the "length of the top of the bookcase, measured along the attic ceiling" will be the hypotenuse of a right triangle, the length "AB". We have both the angle between AB and AC and the length of AC (3.24 meters), so we can use trigonometric identities.
The cosine of the 40 degree angle between AB and AC is equivalent to the length of AC divided by the length of AB. Equivalently, we have:

where "h", the hypotenuse, is the length we want. Rearranging the formula to solve for h we have that

which is 4.2295... meters. Converting to centimeters (multiplying by 100) we have that h = 422.95... centimeters, or if we round the value, h = 423 centimeters.
To get the greatest possible quotient, you need the biggest possible
dividend and the smallest possible divisor.
96,432 divided by 225 = 428.5666... <== greatest possible
23,469 divided by 522 = 44.9597... <== smallest possible
320 ft in perimeter and 200 ft in area