Sectors of Circles 7.2.

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Lesson 7-2 Sectors of Circles.

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Presentation transcript:

Sectors of Circles 7.2

Formulas in Degrees

Formulas in Radians Another way that you can write the area formula…

Example 1 A sector of a circle has arc length 10cm and a central angle .5 radians. Find the radius of the circle and its area.

Example 2 A sector of a circle has arc length 6cm and area 75cm². Find its radius and the measure of its central angle.

Example 3 A sector of a circle has a central angle of 30 degrees and a radius of 5cm. Find its arc length and its area.

Homework Pg. 264 (1 – 7 odd)

Perimeter of a Sector and Apparent Size Examples A sector has a perimeter of 16cm and an area of 15cm². Find all possible radii.

Apparent Size refers to the fact that when you are further away from an object it seems smaller, but as you move closer to that object the size of the object appears to get larger Jupiter has an apparent size of .01 degrees when it is 8 x 10⁸ km away from Earth. Find the approximate diameter of Jupiter.

Example 2 A man standing 350m from the Eiffel tower looks up so that the angle between ground and the top of the tower is 50 degrees. Estimate the height of the tower.

Circular Distance A CD player with a diameter of 6 inches turns at 35 revolutions per minute. Find the distance that a point on the edge of the CD would travel in one minute.

Practice Pg. 264 (2-8 even, 9, 11-15odd)