What are the answers to these 4

Step-by-step explanation:

Center- the origin of the circle

diameter- a line that goes through the origin and hits the opposite side

point of tangency- where the tangent line hits the circle

secant- a line that intersects a circle in two points

tangent-a line that touches the circle at exactly one point

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.

215.92 dollars is the answer