Maths help please

[Pudd]

1: How do you do direct and indirect variation?
Example:
The burning time, t minutes of a candle varies directly as its height, h, millimetres.
A candle with a height of 75 millimetres burns for 180 minutes
What is the burning time of a 40 millimetre candle. * Please use this symbol for a substitute of the variation symbol: {}

2: If you have a rectangle with a cross from corner to corner at all four corners, and have the length and bredth how do i figure out the length of one of the lines that make up the cross? (Shown in the picture)

Thanks for your help

[Magus]

Eh? I am not good at the first one.

I am into teh geometry

I will answer the second one.

Using Pythagoras theorem.

Let us consider line A = 5 and B = 3 and C =?
C is the hypotenuse, A is the adjacent(base) and B as the opposite(90 degree line?)

We need to look into the line C
So, by using that theorem.

C^2 = root of A^2+B^3

C^2 = root of25+9 = 34

C^2 = root of 34 = 5.830... /and it goes on - You do teh root.

So, it is 5.8 CM.

Am I wrong? No Idear.

[Malcolm Tucker]

I've attached my workings for both problems, one for each problem. I did my best to explain it in Simple English. Hope it helped :) If you can't see the attachments properly, I'll be happy to send them to you.

DISCLAIMER: I'm not sure the method I used for Probem 1) was the one you were hoping for. I just used arithmetic and logic to work it. Sorry if it's not what you were hoping for.

[Obscene Eyedeas]

The first 1 i believe can be solved by first converting the 180 minutes to seconds giving you 10800 seconds. so it takes 75 millimeters 10800 seconds to burn. now divide the 10800 by 75 to find out how long it takes 1 millimeter to burn this gives you 144 seconds. then multiple this by 40 to find out how long it takes 40 millimeters to burn for this you get 5760 seconds then divide by 60 to convert it to minutes and if my calculations are correct it takes 96 minutes.

as for your second problem i can't make out the picture on my phone sorry. i hope that helped

[Pudd]

Thanks for the help guys.
Although i still need help on the variation one, using the methods. All i can remember with direct variation is that If a {} b Then it would be a straight line on a graph.
Any further input on this will be greatly apprectiated

[kumarrage]

Looks like simple grade 3 arithmetics and geometry.

[Nickk XD]

Are you for real?

This is Algebra II (advanced algebra) material which is usually done in grade 10 or 11...depending on how well you are at math.

Looks like simple grade 3 arithmetics and geometry.

[Garrett14]

jeez thats hard

[Magus]

Thanks for the help guys.
Although i still need help on the variation one, using the methods. All i can remember with direct variation is that If a {} b Then it would be a straight line on a graph.
Any further input on this will be greatly apprectiated

I am really bad with polynomials in different variables and algebra. Arithmetic progression+Geometric progression, statistics are my enemy. The rest are fun :P

[Pudd]

If people are having as much trouble with that variation question as i am then try this one.
V varies indirectly as W and T
Basic formula:

V {} W/T
100 {} 5/10

Question: Solve:
V {} 3/16

Sidenote: That is a question from a maths past paper i was doing yesterday and it totally stumped me.

Looks like simple grade 3 arithmetics and geometry.
Care to give your two cents then? Or are you just here to knock people who need help?
This is intermediate II classwork in the Scottish curriculum. Im in my 4th year of high school. Nearing my 5th.

Also, for question 1. Do i disregard one of the diagonal lines to get the right angle to use pythagoras thorem?

[Malcolm Tucker]

Also, for question 1. Do i disregard one of the diagonal lines to get the right angle to use pythagoras thorem?

Yes you can. They are both the same length no matter what so it makes no difference (:

[NeedyTeen]

the second one look like Pythagoras theorm as said above.however, the first question I havent yet taken so sorry.