Question

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Answer 1

I'm quite confused. i dont know now T.T



arc length:
l = 2(theta)(r)(theta/360)
l = 2(90)(5)(90/360)
l=225

225x4 = 900
perimeter is 900cm

Answer 2

arc length :
\(\large l = 2 (\theta)r \frac{\pi}{360}\)

now try

Answer 3

oh, wrong formula. ok let me solve it:)

Answer 4

This is just a thought, but wouldn't the perimeter of the shaded region be equal to the circumference of a circle with a radius of 5 cm?

Answer 5

Or, you can see that there are four quarter arcs of radius 5
which give u 1 complete perimeter of circle of radius 5

Answer 6

^^ Yes :)

Answer 7

my arc length is 7.85
so.. my perimeter of the shaded region is 31.42 approximately. is that right?

Answer 8

\(\large \color{red}{\checkmark}\)

next try if you get lncognlto's suggestion...

Answer 9

ah, yes, thanks.
and yup, what he said was right:) I just need a complete solution though:) thanks guys

Answer 10

both methods are considered complete solutions :) u wlc :)
however ur teacher wud get more impressed if u do the lncognlto's method...

Answer 11

oh, haha, alright, will do that :)

Answer 12

good :D

Answer 13

@ganeshie8 , if this is the problem..
would the formula still be 2(theta)(r)(pi/360)
or it should be 2(theta)(2)(pi/180)?

Answer 14

Alright, here is the original formula :-
arc length \(l = r\theta\)
\(\theta\) is in radians

Answer 15

to convert given \(\theta\) degrees into \(\theta\) radians, u multiply \(\frac{2\pi}{360}\)
which is same as multiplying \(\frac{\pi}{180}\) :-

arc length \(l = r \theta \frac{2\pi}{360}\)
\(\theta\) is in degrees now

Answer 16

for the triangle, did they give u any dimensions ?

Answer 17

thank you so much.
yep, ill post my solution later for checking:)

Answer 18

May I give another thought? xD

Answer 19

sure:)

Answer 20

sure :)

Answer 21

If this triangle is equilateral, then the angles of each of the sectors is going to be 60 degrees. Thus three sectors together make 180 degrees, or half a circle. So the perimeter of the shaded region would then be equal to half the circumference of a circle with the radius equaling half the length of a side of the triangle.

Answer 22

oh, that's right. smart one. Hahaha. will remember that:)

Answer 23

60 + 60 + 60

and

180

which one save u time ha ? I'm sure ur teacher wants u do this exactly as lcognlto suggests !

Answer 24

i believe so too:)