A Fraction Math questions thats confusing, Help please!!? - round post swing set blueprints
Jim wants to buy cement to anchor two posts for a swing that is under construction. He dug two round holes with a diameter of 12 cm and 40 cm deep. He wants to fill each with concrete around the support beam of the rectangular 3 1 / 2 inches by 5 1 / 2 inches. Each of the 80 pounds of cement with water to 0.6 cubic meters of concrete mix. How many bags of cement must be purchased for the job?
Thursday, January 7, 2010
Round Post Swing Set Blueprints A Fraction Math Questions Thats Confusing, Help Please!!?
3 comments:
The area of the beam that will be below ground, is 40 * 3 1 / 2 * 5 1 / 2 = 770 cubic inches.
The area of each hole is pi * 6 cm ^ 2 * 40 * = 1440 cubic feet.
This is about 4523.9 cubic inches.
We will therefore 4523.9 to 770 cubic inches of concrete in each hole, making a total of 7507.8 cubic meters of concrete required.
There are 12 ^ 3 = 1.728 cubic inches in a cubic foot, then you'll 7507.8 / 1728 = need
Approx. 4.35 cubic meters of concrete. If a bag is 0.6 cubic meters of concrete, which required
4.36 / 0.6 = 7.2 bags
But since the hardware is not likely to be sold 1 / 5 of a bag, you need to buy 8 bags.
The top hole is a circle. Do you know how to calculate the area of a circle?
Do you think that is the 12 "is mentioned, the diameter of the circle and half of what is the radius of the circle?
(far from the center to the edge?)
Have you noticed that the response is called for in the measurement of cubic meters, compared to 0.6 cubic meters of luggage?
Did you know that the area of a circle pi (3.14) by the square of the radius is multiplied? Since the radius is 1 / 2 feet, then
Square of the radius is 1 / 4 meters and the area is 1 / 4 x 3.14 square meters. (or simply 3.14 divided by 4)
Of course, the shape of the concrete used is a form of absence. What do you say? Well, this place is in it. "So the figure are those of the post and subtract the area of the circle.
The cross section of the post is 3 1 / 2 x 5 1 / 2 inches. Enjoy a figure and divide by twelve to the square meter instead of inches to be square. Drag the area of the circle.
Now it will becomeArea of the strange shape (square feet) is actually the cement around the post. Take advantage of this area and "development" over the entire length of the hole. That's ... Multiplied by the length of the hole that is 40/12. (divided by twelve in order in the feet, of course.) [Of course, you say if your child is very clever, that since there are two positions to be reduced from twelve to six to Nuber here and save a lot of work. .. but claim that they do not read that make it difficult part, that
you! ]
This question is now, the volume in cubic meters of cement into a hole. Remember, there are two holes. So, you multiply that amount by two and Wil have a total volume of cement needed (in cubic meters). Compare that with 0.6 cubic meters of cement produced by the bag and see how many bags.
And of course, what happens to the head of each is here that the cement supplied in bags of 90 kilograms and not 80!
Whether for school!
(Out of six instead of twelve annual dividend is the same as multiplying by two!)
What this question is really asking, what is the volume of concrete is needed to fill the holes. Because the holes have a rectangular beam on them, it is necessary to take into account the volume of the carrier.
This means that the actual volume is filled with concrete, the volume of the hole itself, less the volume of the carrier.
After you establish the extent that the results divided by 6 cubic meters, how many bags of cement you need to determine.
Make sure the equation for the volume of a cylinder holes and the volume of the bar as rectangles.
Good luck!
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