Showing posts with label angle radius arc length. Show all posts
Showing posts with label angle radius arc length. Show all posts

Thursday, December 6, 2012

How to find arc length, when given the radius and angle?

Q. The radius of circle is 9 cm
and the angle is 7pi / 4

the same for this one:

radius is 4.93cm
angle is 4.67 radians

A. example
circle: figure out your circumfrence...lets say its 10cm and the angle they give you is
20 degrees (20°00'00")

20°/360°= x/10cm
x is the arc length your looking for
cross multiply;

(10cm x 20°) ÷ 360° = x

so arc length of a 20° slice is 0.55cm

My point is this can be solved by cross multiplication.
I dont use rads very much so i usually convert to dms


check math.com for good examples

Find the arc length subtended by a central angle of 30° in a circle of radius 4 and radius 5?
Q. How would you even do a problem like this? I am in Pre-Calculus but have like no concept of Trigonometry.

A. draw a diagam. That might help

What is the arc length of a segment along a circle of radius 22inch subtended by an angle of 120 degrees?
Q. An example quiz question that is giving me a hard time

A. Am I to understand that you want the arc length of one-third of a circle with 22inch radius? Or rather, you want one-third the circle circumference?




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