Find the grade of the road (recall that the grade of a road is its slope written as a percent) its a 20foot grade and a 3 feet incline if that makes sense
2006-07-19 13:29:13 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
If by this you mean it goes up three feet for every twenty feet out, this is a simple problem. The grade is 3/20 = 0.15, or 15%.
However, if the road (hypotenuse) is 20 feet and the y-component (how much is goes up), then you need to use the Pythagorean theorem to determine the x-component.
x² + 3² = 20²
x² + 9 = 400
x² = 391
x = √(391) = approx. 19.77372
The grade of the road would be the slope, Δy / Δx, or
3 / √(391) = approx. 0.15172.
The grade is approx. 15.172%.
2006-07-19 13:40:50 · answer #1 · answered by Anonymous · 1⤊ 0⤋
I'm not sure if I understand the question. Every 20 feet, the road elevates 3 feet?
Louise is correct. 3/20 = Grade of the road = 0.15 = 15 Percent
2006-07-19 20:41:49 · answer #2 · answered by Michael M 6 · 0⤊ 0⤋
20² = 3² + x²
â(20² - 3²) = x²
= 19.7337.....
Grade = (3/19.7337...) x 100% = 15.171....%
2006-07-19 22:22:28 · answer #3 · answered by Brenmore 5 · 0⤊ 0⤋
don`t know. got me stumped~!
2006-07-19 21:36:20 · answer #4 · answered by Carol H 5 · 0⤊ 0⤋