A shark descended 23.7 feet to catch a fish. The shark is now at − 65.50 feet. What was his starting point?

Your equation would be
x - 23.7 = -65.50

to solve the equation
add 23.7 to -23.7 and -65.50

your answer would be
-41.8

if the shark descended 23.7 feet and is now at -65.50 feet, the shark was originally at -41.8 feet

hope this helps :)

Yes i could be the length of the triangle