Can someone explain to my why sin(90)=1

On the unit circle: the end of the terminal side of a 90 degree angle is (1,0) where 1 is the value of sin(90°) and 0 is the value of cos(90°)

On the graph of sine: 90° =  radians. if f(x) = sin(x) in radians, f() = 1/2

There is 240 red cars and there is 400 blue cars because 240/3=80 and 80*5=400