If you take a random pen, the length is assumed to be a normal distrubution. The expectation-value is 120 mm, and the standard deviation is 20mm.

We take this random pen and use it as a hypotenuse on a right triangle. With one cathethus that is exactly 72mm. Decide an approximation of the expectation-value and the standard devotion for the area of the triangle.

I am stuck and would appreciate some help