What is the slope of the following equation? y =- 1/2×+1

The physical fitness of an athlete is often measured by how much oxygen the athlete takes in (which is recorded in milliliters per kilogram, ml/kg). the mean maximum oxygen uptake for elite athletes has been found to be 60 with a standard deviation of 7.2. assume that the distribution is approximately normal.

What is the length of the unknown leg in the right triangle ?

Can someone check if i did this right since i really want to make sure it’s correct. if you do you so much