trigonometry

[fervent wren]

I don’t understand the formula given. Please explaination and working.

[soft flame]

1. Wait patiently for a helper to come along.
2. Once someone helps you, say thank you and close the thread with: ```diff
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[jovial wagon]

Notice that AOC is just a sector of a circle meaning OA=OC=9 , hence the triangle is iscoceles

So u hv all 3 sides

Oh wait I didn't even read

U don't understand the formula for arc length?

Is it in degrees or radians

[fervent wren]

yes

rad

[jovial wagon]

Thank god

K

[fervent wren]

the formular is s = r \theta

[jovial wagon]

Yh

So

[fervent wren]

and i dont get it how to get the ans

[jovial wagon]

Imagine

[fervent wren]

yes

[jovial wagon]

U take the angle theta

And then scale it by r

Cuz when it's just the angle

Tbhas no perimeter

It doesn't matter how large u draw the angle size right

The angle thing

[fervent wren]

i think so

im new to this topic actually

the teacher just explained it roughly and im confused

[jovial wagon]

Yh so the formula just scales it by r, hence giving it some perimeter

K so imagine like a rubber band

And its sole purpose

Is to tell u that 'hey, I am 360 degrees'

It doesn't matter what it's circumference is

[fervent wren]

mhm

[jovial wagon]

Now u stretch the rubber band form all sides

Now it's still a rubber band

Its just bigger

That's essentially what the formula doesi

It multiples the angle by some scaling factor, it scales the angle

And it gives it a new attribute (it's curved length)

[fervent wren]

but how do i find the theta if i have the radius but not arc length

[jovial wagon]

U can find theta using cosine rule

Because u have all sides of the triangle

[fervent wren]

oh

[jovial wagon]

Have u done cosine rule?

[fervent wren]

yes for yr 9

c2 = a2 + b2 – 2ab cos?

hello?

[gray coral]

yes

[fervent wren]

oh. tysm

[fervent wren]

can i say i still dk how 💀

[gray coral]

15² = 9²+9²-2×9×9×cos(theta)
theta = ...

[fervent wren]

oh

do i move cos aside into cos^-1?

[gray coral]

yes

[fervent wren]

alr

i got it thanks

[gray coral]

urwelcome

[jovial wagon]

Battery ran out then I had to go srry

Ofc swindle came in clutch

[marble cosmos]

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