The top of a vertical fencepost is 3m, 12 cm (3 meters, 12 centimeters) above level ground. At 9 a.m., the shadow of the fencepost is 7m, 32 cm long. At the same time, the shadow of a nearby building is measured to be 99m, 50 cm long. How tall is the building, correct to the nearest cm?
I've had severl solutions so far....
41m, 51 cm
38m, 19 cm
42m, 41 cm
40m, 19 cm
2007-01-27 03:28:12 · 7 answers · asked by chris 2 in Science & Mathematics ➔ Mathematics
42.4098 mtr ( or 42 mtr, 41 cm) is the right answer.
Ht of bldg = ht of pole ( length of bldg shadow) / ( length of pole shadow)
2007-01-27 03:35:16 · answer #1 · answered by RMG 3 · 0⤊ 0⤋
Classic means to determine the height
the ratio of the height to the shadow is the same for both the building and the fence post
Let big H egual the height of the building and little h equals the height of the post. The shadow of the building is big S and the post is little s.
H/S = h/s solve for big H
H = S (h/s) = (99.5 meters)(3.12meters/7.32 meters)
H = 42.41 meter or 42 meters and 41 centimeters
2007-01-27 03:39:02 · answer #2 · answered by lostlatinlover 3 · 1⤊ 1⤋
First thing to do is draw two right triangles. These triangles are going to be similar because their angles are the same.
Then label all the sides you know.
You then make a ratio. 3.12/7.32 to x/99.5
You cross multiply. 99.5*3.12/7.32
The answer is x~42m, 41cm
Your third answer is correct
2007-01-27 03:39:52 · answer #3 · answered by Barb 1 · 1⤊ 1⤋
42m, 41cm is correct. the buildings and shadows form similar triangles at a given time. the sides are proportionate.
2007-01-27 03:34:03 · answer #4 · answered by Anonymous · 0⤊ 1⤋
i got 42m, 41 cm.
2007-01-27 03:38:37 · answer #5 · answered by music fan 2 · 1⤊ 1⤋
I got 92m 18cm? Why have I got this?
2007-01-27 04:17:13 · answer #6 · answered by Anonymous · 0⤊ 0⤋
3.12/7.32=x/99.5
x =99.5*3.12/7.32 = =42.4098 = 42.41 meters
2007-01-27 03:40:06 · answer #7 · answered by ironduke8159 7 · 0⤊ 1⤋