A circle is subdivided by a central angle of 90 degrees. The length of the subtended arc is 25 mm. What is the radius of the circle?

A:
B:
C:
D:

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Step-by-step explanation:

This the arc is 90 degrees and there are 360 degrees in a circle, it makes up of the circle. Therefore, its length will be of the circumference. Since its length is 25 mm, the circumference is then . The circumference of a circle is given by , where is the radius of the circle. Therefore, we can set up the following equation and solve for :

Solving, we get:

.

c. y = 1/4 x + 5

step-by-step explanation:

first, put the equation of the line on the graph into slope-intercept form

(y = mx + b):   y = -4x + 8

second, a perpendicular line has to have "an opposite/reciprocal slope" to the original slope. so, find the "m" value in your original equation (it's -4, right? )

original slope: m = -4   perpendicular slope: change the sign to its opposite and find the reciprocal ("flip" the number)

new slope is now positive (b/c the original slope was negative 4), and it's 1/4 (not the original slope of 4 or 4/1)