Question

This is a cross section of the design of a bookshelf.

Answer 1

Answer:

25 in

Step-by-step explanation:

$a^{2} +b^{2} =c^{2} \\15^{2} +20^{2} =c^{2} \\225+400=c^{2} \\c^{2} =625\\c=\sqrt{625} \\c=25$