I need help, and a step by step explanation! :)

90°

Step-by-step explanation:

There is no work. We know the right angle in the triangle and  the x are supplementary. Meaning, they add up to 180 degrees.  Therefore, 180-90 = 90. Think of it as a full triangle. If the 40 at the top was not half, but a full triangle, the 40 at the top would become 80. The 50 in the bottom left would mean there would be a 50 in the bottom right when you mirror the triangle. Therefore, you also need x to be 90 to make it a right triangle.

i dont get it. where are the "descriptions"?

step-by-step explanation:

the multiplicative inverse of a fraction a/b is b/a. for the multiplicative inverse of a real number, divide 1 by the number. for example, the reciprocal of 5 is one fifth 1/5 or 0.2, and the reciprocal of 0.25 is 1 divided by 0.25, or 4.