Which is the correct label for a right angle in the figure? (check picture for options and figure)

Really need on these. i have no idea what to do

Simplify 5 square root of 7 end root plus 12 square root of 6 end root minus 10 square root of 7 end root minus 5 square root of 6 . (1 point) 5 square root of 14 end root minus 7 square root of 12 5 square root of 7 end root minus 7 square root of 6 7 square root of 12 end root minus 5 square root of 14 7 square root of 6 end root minus 5 square root of 7

The longer leg of a 30° 60° 90° triangle is 16 times square root of three how long is a shorter leg