length of common tangent?? (1 Viewer)

[5647382910]

I know what a common tangent is but what are you actually being asked to find in this:

two circles of radii 5cm and 8cm touch each other externally. Calculate the length of the common tangent

Cant the length of the tangent be anything?

 

[lyounamu]

I know what a common tangent is but what are you actually being asked to find in this:

two circles of radii 5cm and 8cm touch each other externally. Calculate the length of the common tangent

Cant the length of the tangent be anything?

That's interesting. I don't know either. The wording of the question is confusing.

 

[5647382910]

man wtf, this is fitzpatrick, the next 4 q's ask for the length of the common tangent, this is bullshit

 

[Timothy.Siu]

man wtf, this is fitzpatrick, the next 4 q's ask for the length of the common tangent, this is bullshit

there is,
u can find it...i'll do it soon,
edit: this is if i think i know what i'm trying to find.

 

[gurmies]

is the answer 4sqrt10 cm ?

 

[5647382910]

is the answer 4sqrt10 cm ?

ye, but what did u calculate?

 

[Timothy.Siu]

ye, but what did u calculate?

yeah i got that too,
u just draw a diagram, and using tangent to centre is right angle, u can make a triangle with 13 as the hypotenus (8+5) and a side of 3, so the other side is square root 160
edit: i'll draw it in paint

 

[Timothy.Siu]

and u can like sorta shift the 13cm side down, and make the triangle

 

[gurmies]

Agreed. I'm so bad at drawing using paint, thus I can't post my solution But yeah, draw a line from the centre of the SMALLER cirlce, meeting the larger radius to the tangent at a right angle. Therefore, the smaller part will be 3 cm, and the larger will be 5 cm. Now use pythagoras' theorem and say 13^2 - 3^2 = 4root10. That's also the length of the common tangent..

 

[lyounamu]

and u can like sorta shift the 13cm side down, and make the triangle

Never seen that kind of question before. But I guess it's part of the learning curve. Thanks for posting that up,

 

[5647382910]

lol, i was finding the tangent through the point of contact
thanks for the help guys

 

[lyounamu]

lol, i was finding the tangent through the point of contact
thanks for the help guys

The common tangent is not only restrctied to the tangent through the point of contact.

 

[madsam]

lyounamu:

My HSC subjects = ​

(maths + business +bio + english + cosmo) + i(sor) ​

Thats hilarious.... but it really shouldnt be =\
do you do 4unit?

 

[lyounamu]

lyounamu:


Thats hilarious.... but it really shouldnt be =\
do you do 4unit?

Why shouldn't it be?

4 subjects are real but one is just an imaginary subject.

Yeah, I do 4 Unit Mathematics.

 

[DrFunk]

whilst I am amused by your sig, it isn't perfect as i is the imaginary part, and in the form x +iy y stands in place of a real number. So yeah... You're trying to say religion is imaginary but kinda failed...

 

[lyounamu]

whilst I am amused by your sig, it isn't perfect as i is the imaginary part, and in the form x +iy y stands in place of a real number. So yeah... You're trying to say religion is imaginary but kinda failed...

Hey, the order doesn't really matter (in this sig). I am aware that i goes next to the number but I cannot be bothered to change it.

 

[youngminii]

Hey, the order doesn't really matter (in this sig). I am aware that i goes next to the number but I cannot be bothered to change it.

I think what he thinks is that you tried to make SoR 'imaginary'. As in, SoR = i

Anyways DrFunk, it is a joke, and it is supremely.. stupid to talk about it so literally

 

[lyounamu]

I think what he thinks is that you tried to make SoR 'imaginary'. As in, SoR = i

Anyways DrFunk, it is a joke, and it is supremely.. stupid to talk about it so literally

Nah, actually I was trying to make it as an imaginary part.

I really am not good at copying from someone else's idea.

 

[addikaye03]

Nah, actually I was trying to make it as an imaginary part.

I really am not good at copying from someone else's idea.

Did you copy from that VDS guy? and what 4U textbook do you use dude?
and how do you think u went at 3u this year?