urgent math question

help with this question please urgent homework

what rules do i use? is trig needed? I have tried this question for over 20 minutes if anyone could spare any bit of their time helping me it would be greatly appreciated

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Reply 2

the bear

Original post by dontevenknow2

what rules do i use? is trig needed? I have tried this question for over 20 minutes if anyone could spare any bit of their time helping me it would be greatly appreciated

you have not given us all the question.

I have linked it

I believe it is a Duck's head, however I am not an expert in Modern Art.

Reply 5

username4591252

What do we need to work out???

Reply 6

username4342852

ARC ADC and ob is 12cm

Reply 7

Orlednnw

Workout angle AOB (Using SOH CAH TOA) and times it by 2 (to account for COB). Convert it to radians.
then do 2Pi - (the answer you just worked out) to get Theta for the major Arc
Length of Arc= Theta * r
Therefore, times that answer by 7

(edited 5 years ago)

Reply 8

username4591252

Okay yh you have to use some trig on triangle OAB or OCB (they're congruent so it doesn't matter) to work out angle AOB or COB (they're the same value). That should be a good starting point.

Please ask if you need more help

Original post by dontevenknow2

ARC ADC and ob is 12cm

Reply 9

username4342852

im so stuck please help me i used trig and i got cos -1 7/12 what now please help me

Reply 10

username4591252

Okay so now you have that angle you can work out the angle of the arc ADC

Reply 11

username4342852

so i got 54.3 as my answer so what do i do now ?

Reply 12

username4591252

Angle AOC is just double the 54.3 degrees. To work out the angle of the arc you have to do 360-2x54.3 (angles in a circle add up to 360)

Then you can work out arc length by using arc length = 2 x Pi x radius x (angle of the arc/360)