Highway partol: A highwasy partol plane flies 3 mi above a level, straight road at a a steady 120 mi/h. the pilot sees an oncoming car and with radar determines that at teh instant the line of sight distance from ot car is 5mi, the-line-of-sight distance is decreasing at the rate of 160mi/h. find the car's speed along the highwasy.
2. The diameter of a tree was 10 in. during the following year, the circumference increased 2 in. abour how much did the tree's diameter increased? The tree's cross- section area?
my answer: it 6.28 in is this right please let me know. i don;t know how to find the trees cross section.
please help me i tried so many ways to solve these problem!
2007-10-30 05:56:57 · 1 answers · asked by Facilitate 1 in Science & Mathematics ➔ Mathematics
1. This makes a right triangle of dimensions 3, 4, 5. Since the 5 dimension is changing at a rate of 160 mph, the 4 dimension (the car's speed) is changing at 4/5*160 = 128.
2. C = πD, therefore:
... ΔD = ΔC/π = 2/π
... A = πD²/4, therefore:
... ΔA = πΔD²/4 = π(2/π)²/4 = 1/π
2007-10-30 06:09:04 · answer #1 · answered by gebobs 6 · 0⤊ 1⤋