In the following problems, compute the radius in inches of the following circles drawn on a computer screen. Two points, with coordinates measured in pixels, define each circle. The first point marks the center of the circle and the second marks a point on the circumference. The radius is the distance between the two points. Assume that a pixel is a dot with diameter of 0.28 millimeters.

(400, 100) and (600, 300)
Radius is distance between center (x1, y,) and point on the circumference (x2, Y2). Distance (r) can be found using the Pythagorean equation:


r = 282.8427 (pixels) * 0.28 (mm / pixel) = 79.1960 mm
r = 79.1960 (mm) * 1/1000 (meter / mm) * 39.37 (inches / meter) r = 3.1179 (inches)
Radius is 3.12 inches (rounded to 2 places)