Arc lengths and areas
13
Mr. Saucedo Milby High School Geometry
description
Geometry HIgh School, lesson, Circles, Areas, Arc Lengths, Sectors, Introduction, Perimeter, Area, Volume Unit
Transcript of Arc lengths and areas
Mr. SaucedoMilby High School
Geometry
Objective:To find partial areas and circumferences of circles.
What you should know…Find the
Circumference and the Area of a circle with diameter 10.
WHAT IS?ARC LENGTH
An arc length is a fraction of the circumference.
The concept…Can you find the arc length of thisSemicircle?
What would the arc length be if we just wanted to use a quarter of the circle?
HOW DO WE FIND ARC LENGHTS?
With the following proportion:
Part of a circumference = Portion of degrees
Whole Circumference Whole: Degrees in a circle
Arc length = Central Angle пD 360
GUIDED EXAMPLE 1Find the length of the arc:
Independent exampleFind the length of the arc AB.
SECTORSWhat is a sector?
AREA OF A SECTORFORMULA:
AREA OF SECTOR = CENTRAL ANGLEAREA OF CIRCLE 360
AREA OF SECTOR = CENTRAL ANGLE пr2 360
GUIDED EXAMPLE 2Find the area of the blue section
INDEPENDENT EXAMPLEFind the area of the shaded region.
HOMEWORKWORKBOOK (BLUE BOOK)
Pages:
