9514 1404 393
Answer:
y = 24
Explanation:
The line marked 'x' is a midline of the triangle, hence half the length of the parallel base line marked '4x-7'. This lets us solve for x and find the lengths of the sides of the triangle.
2x = 4x -7
7 = 2x . . . . . add 7-2x
3.5 = x
Then the horizontal side of the triangle is ...
4x -7 = 4(3.5) -7 = 7
The hypotenuse of the triangle is ...
6x +4 = 6(3.5) +4 = 25
The Pythagorean theorem can be used to find y:
y^2 +7^2 = 25^2
y^2 = 625 -49 = 576
y = √576
y = 24