Answer:
8cm
Step-by-step explanation:
x is similar to the side 12cm.
We know the second triangle is rotated counter-clockwise from the first because similar triangles have the same angle measurements.
Since the angle in the first triangle between 9cm and 15cm is 53°, it can't be similar to the angle between x and the hypotenuse in the second triangle.
Find the scale factor:
Triangle 1/Triangle 2
Divide two similar sides.
6/9 = 2/3
Multiply the scale factor by the similar side to find x.
x = 12*(2/3)
x = 8
