# Maths Exam Stuff...

• Nov 5th 2007, 05:53 PM
Missy_Wattle
Maths Exam Stuff...
Hey...i'm just doing some revision 4 some maths, and i need help with some stuff...
First Question:
Some sun bathers were surveyed when asked "Can you swim 200m non stop? 40% said yes, 30% said no, 20% said they were not sure and the rest said that they could not swim at all...
Represent this information on a Pie Graph below. Show workin' etc...

• Nov 5th 2007, 07:03 PM
CaptainBlack
Quote:

Originally Posted by Missy_Wattle
Hey...i'm just doing some revision 4 some maths, and i need help with some stuff...
First Question:
Some sun bathers were surveyed when asked "Can you swim 200m non stop? 40% said yes, 30% said no, 20% said they were not sure and the rest said that they could not swim at all...
Represent this information on a Pie Graph below. Show workin' etc...

First do you know what a pie chart or graph is? You will find a description here.

Excel has a pie chart option, which you can use to draw the chart, the result
in shown in the attachment to this post.

RonL
• Nov 6th 2007, 01:52 PM
Missy_Wattle
would there be any equations i could use, so i know in future, how to find out on my own?
Would i have to divide a certain number by 360? or what...
I've done this before, i know but i'm kinda rusty.
• Nov 6th 2007, 02:03 PM
Missy_Wattle
also there's one other thing...i have a ladder that's 5 m high and it's leanig against a wall, where the top of the ladder reaches just to the top, and the base of the ladder is 3 m away from the wall.
I'm trying to find out how high the wall would be...would the 3 m at the base, take off the height of the ladder, so in actual the ladder is higher than the wall or...
Would the Formula be: A= Base x Height divided by 2 of what?
• Nov 6th 2007, 02:06 PM
Jhevon
Quote:

Originally Posted by Missy_Wattle
would there be any equations i could use, so i know in future, how to find out on my own?
Would i have to divide a certain number by 360? or what...
I've done this before, i know but i'm kinda rusty.

yes. we know that each response in the pie chart will be represented proportionally on the pie chart, so each take up some (proportional) amount of degrees out of the 360 degrees of the circle.

first you should know that "percent" means out of 100, so 40 percent is 40/100 = 0.4

also, "of" means multiply, so to find 40 percent of 360 degrees, we find

40/100 x 360 = 144

so the 40% who said yes, will take up 144 degrees of the pie

the rest are calculated similarly
• Nov 6th 2007, 02:09 PM
Jhevon
Quote:

Originally Posted by Missy_Wattle
also there's one other thing...i have a ladder that's 5 m high and it's leanig against a wall, where the top of the ladder reaches just to the top, and the base of the ladder is 3 m away from the wall.
I'm trying to find out how high the wall would be...would the 3 m at the base, take off the height of the ladder, so in actual the ladder is higher than the wall or...
Would the Formula be: A= Base x Height divided by 2 of what?

we would use Pythagoras' theorem. if you drew a diagram of the setup, you'd realize that we have a right triangle with a base of 3m and a hypotenuse of 5m, and we want to find the height.

Let the two sides of the right triangle be a and b, and let the hypotenuse be c. By Pythagoras' theorem, we have:

a^2 + b^2 = c^2

here you have a and c, so plug them in and solve for b
• Nov 6th 2007, 02:27 PM
Missy_Wattle
dang... i thought i knew this one...there's the hypotenuse, adjacent, and the other side i've forgotton... can you tell me what ^ means?
• Nov 6th 2007, 02:31 PM
Jhevon
Quote:

Originally Posted by Missy_Wattle
dang... i thought i knew this one...there's the hypotenuse, adjacent, and the other side i've forgotton... can you tell me what ^ means?

it means the 2 is a power

so what i meant was \$\displaystyle a^2 + b^2 = c^2\$

we can only speak of the adjacent and opposite side with respect to some acute angle of the triangle. so you can't use those phrases here
• Nov 6th 2007, 02:47 PM
Missy_Wattle
or instead of that could i go: tan a - opposite by adjacent-3/10- 0.30
• Nov 6th 2007, 02:51 PM
Jhevon
Quote:

Originally Posted by Missy_Wattle
or instead of that could i go: tan a - opposite by adjacent-3/10- 0.30

why would we do that. that is just superfluous. we want to find the height of the wall, by Pythagoras, we get it directly. doing it as you suggested, we would have to use trig to find an angle, and then using that angle and trig again, to find the height. that's just too much work here.
• Nov 6th 2007, 06:26 PM
Missy_Wattle
Complete the table below and graph the equation y = 2 x + 3 on the grid below.

another one says " Use your graph to solve 2 x + 3 = 11 show your working on the graph.
info on attachment....
• Nov 6th 2007, 06:50 PM
Jhevon
Quote:

Originally Posted by Missy_Wattle
Complete the table below and graph the equation y = 2 x + 3 on the grid below.

another one says " Use your graph to solve 2 x + 3 = 11 show your working on the graph.
info on attachment....

just plug in the x-values and solve for y. for example, in the x = 0 column, the y-value under it is given by: y = 2x + 3, so when x = 0, y = 2(0) + 3 = 3. so y = 3 is the corresponding y-value. fill out the rest of the table

for the second question, use your table to plot the points you got and draw the line. then look for 11 on the y-axis. draw a horizontal broken line from the 11 to the line you graphed, and then a vertical broken line down to the x-axis. the line will cut the x-axis at the required x-value
• Nov 7th 2007, 02:16 PM
Missy_Wattle
another one is... A Scaled drawing of my barn measures 10 cm in length and 5 cm in width. If the scale used is 1:100, what are the actual dimentions of my barn?
• Nov 7th 2007, 06:32 PM
Jhevon
Quote:

Originally Posted by Missy_Wattle
another one is... A Scaled drawing of my barn measures 10 cm in length and 5 cm in width. If the scale used is 1:100, what are the actual dimentions of my barn?

your barn is very small, how many animals you got in there? the scale is 1:100, that means for every 1 cm on the diagram, we have 100 cm in actuality. so the barn is 10(100)cm by 5(100)cm = 1000cm by 500cm = 10 meters by 5 meters, ok, so that's not THAT small, but it's still small