#1 (permalink)

Ok i had no idea where to post this shit so im puttin it in here. I gotta finish these or i get a couple of after school detentions.

A lawn area is made up of a semicircular region with diameter 6.5 meters and a triangular region of length 8.2. Find the total area of lawn, to one decimal place.

and

An L-shaped concrete slab being prepared for the foundation of a new house is made up up of two rectangles with dimensions of 3 meters by 2 meters and 10 meters by 6 meters.

a) find the total area of the concrete slap.
b) if two bags of cement are required for every 5 square meters of concrete, how many whole bags of cement will needto be purchased for the job.


Oh and if you could show the working out, because i need that or she'll rape me.
Thanks.

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#2 (permalink)

These problems are all about visualizing simpler ways to essentially "break down" what you're looking at.

For example, in problem A, you have a square and a semi-circle. Since you know the sides of the square are all 5cm, you can also deduce that the radius of the circle is 2.5 cm because its diameter is also 5 cm.

To find the area, it is simple: 1/2*pi*r^2(r=2.5) + 5^2

For a more complicated example, look at problem F. The total area shown is 1/2*pi*r^2, but you are also omitting a smaller section of the semi-circle.

You can break up the omitted section into a triangle, and a trapezoid.

Much like the last problem, only with an omission instead of an addition, your formula should be: 1/2*pi*r^2 - (1/2*s1*s2) - 1/2(b1+b2)h

s1, s2: side1 and side2; b1, b2: base 1 and base 2.

I'm sure you know the formulae for these more simple shapes, but I figured I would point this out anyway.

This should at least give you a solid start on your assignment. Any questions, feel free to post/PM.

#3 (permalink)

aight, after reading that I do not want to take trigg.

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Be Different.

#4 (permalink)

Haha...that's not even Trig...that's just the Geometry part lol

Trig is really as simple as sin(x), cos(x), tan(x)...plus maybe just...a few other things? (i.e. sin^-1(x), cos^-1(x), tan^-1(x), sec(x), csc(x), cot(x), all of their derivatives, integrals, and various powers as well) So yeah..just a few haha

#5 (permalink)

Ok thanks alot Kalter, but does anybody have any ideas for the first two questions with the lawn and the L shape?

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#6 (permalink)

Is there no visual to go with any of the world problems, because they could be construed several different ways. My assumption for the first one is that it's a semi-circlular region, much like the first problem on your graphic (problem A), but instead of a square, you now have a triangle. Unfortunately, it doesn't tell you what kind of triangle it is, so it's going to be hard to tell.

However, if my assumption is correct, you would most likely be given an isosceles triangle simply because they are easiest to work with at this stage of the game.

Stikky, have you discussed Pythagorean Theorem at all yet? I ask because that would more than likely help me in telling you how to do that problem.

As for the L-Shaped thing, that's another that could be misconstrued without a proper visual. I really don't know how to set that problem up, to be honest because again...without knowing exactly what shape is at question, it's sort of difficult to set up an area problem.

Answer those 2 questions for me, and I'll help you set up the problems.