Question

used the illustration below to calculate the circumfrence of the cirlcle.

A. 17.5 cm
B. 15.7 cm
C. 31.4 cm
D. 78.5 cm

Answer 1

\[C=2\pi r\]

Answer 2

sorry ignore that line on the right

Answer 3

well it looks as though the hypotenuse of that right triangle....would be the diameter of the circle right?...so how do we find that?

Answer 4

a2+b2=c2

Answer 5

yes! by using the pythagorean theorem of course!

A² + B² = C²
3² + 4² = C²

C = √(3² + 4²)

so C =?

Answer 6

a2+b2+c2 right?

Answer 7

is that right?

Answer 8

A² + B² "=" C²

this is how you solve for a missing side of a right triangle.....for example

the hypotenuse...is equal to the square root of the other 2 sides squared
so

C = √A² + B²

Answer 9

now you already have the 2 other sides....you just want the hypotenuse so plug in your numbers

C = √(3² + 4²)

so C = ?

Answer 10

c=5

Answer 11

right! so now you have...

Answer 12

as you can see...that side (5cm) is acting as the diameter of the circle...

now if we have the diameter.....how do we find the radius??

Answer 13

that line way to the right was an accident when drawing it lol

Answer 14

anyways I got my answe as 15.7

Answer 15

lol yeah I guessed that lol.....and yes very good :))

Answer 16

Thanks!

Answer 17

anytime! :)

Answer 18

really!???

Answer 19

lol please correct me then! I really should brush up on my geometry!

Answer 20

are you sure? because trust me geometry wasn't my best subject lol....so there is a definite possibility....but I felt pretty good about this one :)