The answer is 21.9
Hope this helps good luckkk :)
Answer:

Step-by-step explanation:
The right triangle is also Isosceles. It has two equal angles of 45°.
(hypotenuse)² = 2S²
4 = 2S² => S = √2
Therefore B is the correct answer.
The sum of two numbers:
x + y = 108
The difference of the same two numbers:
x - y = 78
We can use substitution to figure out x and y:
x - y = 78 can be changed to x = 78 + y
We can plug this into the first equation:
78 + y + y = 108
78 + 2y = 108
2y = 30
y = 15
Now solve for x using any of the two equations. I'll use the first equation since it's easier:
x + 15 = 108
x = 93
Okay well, if you make a graph, Point A (7,0) and Point B (4,6) are in the top right quadrant. and Point C (1,1) and Point D (5,3) are in the top left, top right, and bottom left quadrant (I'll link a photo of the graph.)
so the lines intersect and make it perpendicular