SRL Archive - Mathematics

there's a group of problems on this diagram.
i'll list the problems, and if i have them, answers

#1: measure of arc EFG Answer: 160 degrees
#2: measure of arc EHG Answer: 200 degrees
#3: length of arc EFG Answer: approx 19.55
and now #4… you need to find the length of ehg. so what i did was find the circumference using c=7*pi, which came out to approx 21.99. i deducted 19.55 from 21.99, and that obviously came out wrong… i know that i should just do L=(200*pi*7)/180 to find that arc length, but still, this way should work, and it didnt.

EDIT: DUHHHHHHHHHHHHHHHHHHHH its C=14*pi… /facepalm

Diagram's not to scale. And EFG isn't 160 if FDG is 80 degrees. FG would be 160 if FDG is 80 degrees, wouldn't it?

Why not use s=r(theta) [the equation for arc length]? theta is in radians.

160 degrees = 8pi/9
200 degrees = 10pi/9

EHG arc -> s= 7(10pi/9) = 70pi/9 = 24.42
EFG arc -> s= 7(8pi/9) = 56pi/9 = 19.54

Circumference of Circle = pi*diameter [not radius] = pi*14 = 43.98

EHG arc + EFG arc = 24.42 + 19.54 = 43.96

So these both agree with eachother.

From: HyperSecret
Why not use s=r(theta) [the equation for arc length]? theta is in radians.

160 degrees = 8pi/9
200 degrees = 10pi/9

EHG arc -> s= 7(10pi/9) = 70pi/9 = 24.42
EFG arc -> s= 7(8pi/9) = 56pi/9 = 19.54

Circumference of Circle = pi*diameter [not radius] = pi*14 = 43.98

EHG arc + EFG arc = 24.42 + 19.54 = 43.96

So these both agree with eachother.

From: Nava2

perhaps because i'm a freshman in highschool just taking college prep geometry? ;)

From: i luffs yeww
Diagram's not to scale. And EFG isn't 160 if FDG is 80 degrees. FG would be 160 if FDG is 80 degrees, wouldn't it?

of course it's not to scale. it's a quick ms paint

and i forgot to mention that D is the center. And if an angle's vertex is the center of the circle, then the measure of the angle and the measure of the corresponding arc are the same.

From: Nava2

Get that shit out of here… :D

I took CP Geometry too as a freshman…