John puts the base of a `13` foot ladder `7` feet from the wall of his house. How far up the wall does the ladder reach? Round your answer to two decimal places.

7 feet

13 feet

feet  

Box 1: Enter your answer as a number (like 5, -3, 2.2172) or as a calculation (like 5/3, 2^3, 5+4)
Enter DNE for Does Not Exist, oo for Infinity