how do i prove that the angle between a tangent and a radius is 90 degrees?

2 answers

One way is to draw a chord of the circle that is bisected by a radius vector. By similar triangles you can show that the angle between the chord you drew and the radius line is 90 degrees. Then shrink the length of that chord until t just barely cuts the circle.
o great job greg o is it mames im sorry kanes