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Geometry for School and Home
Activity 3.8
Assignment 3.9
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Assignment 10.18
Areas with Circles
Objectives
Apply a formula for areas of rings.
Find areas of figures that are composites of circles and polygons.
Find areas of segments of circles with right central angles.
About Geometry Worksheet Assignment 10.18:
Assignment 10.18 is an introduction to areas of rings, composites of areas of circles and polygons, and areas of segments of circles.
Prerequisite Skills: Calculate the area of a circle (Assignment 10.16). Identify the radius and diameter of a circle (Assignment 10.1). Find areas of rectangles (Assignment 8.3). Find areas of right triangles (Assignment 8.6).
Definitions: A ring is a region between two concentric circles.
A segment is the region between a chord and its intercepted arc.
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Theorems: The formula for the area of a ring is: A = R - r (R is the radius of the larger circle; r is the radius of the smaller circle)
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The formula for the area of a segment is: A = 1 r - 1 r
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