The sum of two numbers is 36. find the numbers whose sum of their square is in minimum

Can someone me with my math problems i have a bunch. i will give brainliest and lots of pleeeaaasssee

Find the length of the normal and the angle it makes with the positive x-axis. (see pictured below)

Sara goes on a slingshot ride in an amusement park. she is strapped into a spherical ball that has a radius 3*10^2 of centimeters. what is the volume of air in the spherical ball? use this formula: volume of a sphere=4/3pi,r^3 , where r is the sphere’s radius.