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schepotkina [342]
3 years ago
6

The stopping distance of a car is modeled by the function d = 0.05r(r + 2) where d is the stopping distance of the car measured

in feet and r is the speed of the car in miles per hour. If skid marks left on the road are 75 feet long, how fast was the car traveling?
Mathematics
1 answer:
adell [148]3 years ago
3 0

Answer:

The car was moving approximately at a speed of 37.74 miles per hour.

Step-by-step explanation:

We are given the following in the question:

The stopping distance of a car is given by

d = 0.05r(r + 2)

where d is the stopping distance in feet and r is speed of the car in miles per hour.

The stopping distance is 75 feet, we have to find the speed of the car,

Putting d = 75 in the equation, we get,

75 = 0.05r(r + 2)\\r^2 + 2r = 1500\\r^2 + 2r-1500 = 0\\\\r =\dfrac{-2\pm \sqrt{4-(4)(1)(-1500)}}{2}\\\\r\approx -39.74,37.74

Thus, the car was moving approximately at a speed of 37.74 miles per hour.

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Larger PyramidHeight 24 Volume 648

Pyramid Volume = (Area of the Base * Height) ÷ 3648 = Base Area * 24 / 3Base Area = 648 * 3 / 24Base Area = 648 / 8Base Area = 81Base Length = 9
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Slant Height^2 = 4.5^2 + 24^2Slant Height^2 = <span> <span> 596.25 </span> </span> <span><span>Slant Height^2 = 24.4182308941 </span> </span>
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Its base perimeter would be 12.
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d) Ratio of larger pyramid volume to smaller pyramid volume648 / 24 = 27The reason? Volume is a 3 dimensional quantity.  The Larger pyramid is 3 times larger in terms of the base measurement.9 meters vs 3 meters - a factor of 3When we compare volumes, we have to cube this factor.3^3 = 27

Source : http://www.1728.org/volpyrmd.htm

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