Earth is composed of four main layers, starting with an inner core at the planet's center, enveloped by the outer core, mantle, and crust. The inner core is a solid sphere made of iron and nickel metals about 759 miles (1,221 kilometers) in radius.
source: nasa
Air mass, letter a is the correct one
I believe that the perpendicular equation would be the opposite sign and the reciprocal of the original slope. Then you just plug in the x and y coordinate to y=mx+b and solve for b.
y=4x+b
3=4(-4)+b
3=-16+b
b=19
y=4x+19
