hi <3
you can use the sine rule in this.
first calculate the missing angle in the triangle.
we know the angles in a triangle sum to 180 so:
180 - 37 - 90 = 53
now, simply input these values into the sine rule
10/sin(53) = x/sin(37)
rearrange for x:
x = (10/sin53) x sin37
solve to get your answer of:
x = 7.5
hope this helps :)