Answer: 
<u>Step-by-Step Explanation:</u>
Pythagorean Theorem is: a² + b² = c² , <em>where "c" is the hypotenuse</em>

Note: (15)² + (3√11)² = hypotenuse² → hypotenuse = 18

Note: 8² + 15² = hypotenuse² → hypotenuse = 17

Note: hypotenuse not needed for tan

Note: 2² + 6² = hypotenuse² → hypotenuse = 2√10
I really think your is 12 feet and 2 inches
Answer:
AB = BC = AC = 15
Step-by-step explanation:
Since the triangle is equilateral then the 3 sides are congruent.
Equate any 2 sides and solve for x , that is
AC = AB , so
11x - 7 = 6x + 3 ( subtract 6x from both sides )
5x - 7 = 3 ( add 7 to both sides )
5x = 10 ( divide both sides by 5 )
x = 2
Then
AC = 11x - 7 = 11(2) - 7 = 22 - 7 = 15 , thus
AB = BC = AC = 15
Uhhhhhhhhhhhhhhhhhhhuhhhhhhhhhhhhhh