Answer: missing side length = 12.5
Step-by-step explanation:
1. Identify what equation to use
there are 2 side lengths, and no Pythagorean triples present therefore using the Pythagorean theorem a^2+b^2=c^2 would be a good approach
2. plug in numbers
knowing the missing side length is the hypotonus we can plug 6 and 11 for a and b: 6^2+11^2=c^2
3. Solve equation
6^2+11^2=c^2
36+121=c^2
157=c^2
12.52=c | to cancel square (^2) you must square root the number
12.5=c | round