circle question (1 Viewer)

[izi]

im in year 11 and i have an assignment due tomorrow, but i cant do one of the questions:

A circle with centre O has a radius OD with chord AC crossing the radius perpendicularly at B. Find the length of the radius, to the nearest cm if AC = 10cm and BD = 3cm.

 

[Affinity]

let radius = r

OB = (r-3)
AB = (1/2)AC = 5

OA^2 = OB^2 + AB^2

r^2 = r^2 - 6r + 9 + 25

r = 34

r = 34/6 = 17/3

 

[~*HSC 4 life*~]

Originally posted by Affinity
let radius = r



r^2 = r^2 - 6r + 9 + 25

r = 34

r = 34/6 = 17/3

don't you mean 6r = 34?
.: r= 34/6

 

[Xayma]

Originally posted by ~*HSC 4 life*~
don't you mean 6r = 34?
.: r= 34/6

If you really want to get pedantic, Affinity also forgot units.

 

[~*HSC 4 life*~]

hmm isn't izi a vet science student?

edit

B. Veterinary Science @ USyd
class of 2002


how could she be in yr 11? oh well

 

[Grey Council]

hrm, same thing i wondered.

and I think affinity just forgot the 6. the next line is correct.

 

[Calculon]

Originally posted by ~*HSC 4 life*~
hmm isn't izi a vet science student?

edit

B. Veterinary Science @ USyd
class of 2002


how could she be in yr 11? oh well

prob. a brother/sister

 

[~*HSC 4 life*~]

Originally posted by Grey Council
hrm, same thing i wondered.

and I think affinity just forgot the 6. the next line is correct.

yeah, affinity is still bloody smart! lol