12 multiple-choice questions, progressively harder.
On level ground, an instrument 1.80 m above the base level sights the top of a vertical 16.0 m mast in the same vertical plane. The horizontal run is 25.0 m. Find the elevation angle to the nearest tenth of a degree.
Solution
Correct answer: C
Subtract instrument height to obtain the opposite leg.
An eye is 30.030.030.0 m above a horizontal water surface. A point on a boat deck is 2.02.02.0 m above that surface and is seen at depression 25.0∘25.0^\circ25.0∘. All points lie in one vertical plane. Find the horizontal run to the nearest tenth of a meter.
Correct answer: A
Use the vertical difference between the eye and the target, both measured from the same water level.
A straight ramp has sloped length 12.0 m and vertical rise 1.80 m. Find its percent gradient to the nearest tenth of a percent.
Correct answer: D
Percent gradient needs horizontal run, so recover that leg first.
An observer's ground point is 3.03.03.0 m above a vertical tower's base level. The eye is 2.02.02.0 m above that ground. The horizontal run to the tower is 30.030.030.0 m, and elevation is 24.0∘24.0^\circ24.0∘ in the common vertical plane. Find tower height to the nearest tenth.
Correct answer: B
The eye is 5.0 m above the tower’s base level. Add the sight-line rise to that elevation.
From a fixed eye, the top and bottom of a vertical sign are both above the eye's horizontal, at elevations 39.0∘39.0^\circ39.0∘ and 27.0∘27.0^\circ27.0∘ respectively. Their common horizontal run is 18.018.018.0 m. Find the sign's vertical length to the nearest tenth.
The two vertical rises start at the same eye level. Subtract the lower one.
Two equal-height instruments stand on the same straight horizontal line through a vertical tower base, with one station nearer the base. Both sight the same top above eye level. Which angle pair is compatible with this order?
Let the shared positive rise be uuu, near run xxx, and positive station separation bbb. A shorter horizontal run gives a larger rise/run ratio and a larger acute elevation angle.
From one station, an observer measures only elevation angles to the top and base of a vertical segment, both above the horizontal. No distance or length is known. Does this determine the segment’s length?
Let uuu and vvv be the two vertical rises above the eye and ddd the common horizontal run. Doubling all three lengths preserves both tangent ratios.
The same two angles therefore permit a vertical segment twice as long.
A report uses eye height 1.651.651.65 m, elevation 36∘36^\circ36∘ above horizontal, and a 323232 m tape distance measured along sloping ground to estimate a vertical tower's height as 1.65+32tan36∘1.65+32\tan36^\circ1.65+32tan36∘. No ground inclination or base-level difference is recorded. What is the justified conclusion?
Let ddd be the horizontal run and ggg the observer ground elevation relative to the tower base. A supported model would be
The sloping tape length establishes neither ddd nor ggg, so substituting 32 and silently taking zero ground offset is unsupported.
A vertical target is 17.0 m high above level ground. An eye 1.4 m above the same ground is horizontally 23.0 m away, in the same vertical plane. Find the top’s elevation angle to the nearest tenth of a degree.
The opposite leg is the top’s height above the eye.
A straight ramp is 5.05.05.0 m long along its surface and rises at 12.0∘12.0^\circ12.0∘ to the horizontal. Find its horizontal run to the nearest tenth of a meter.
The run is adjacent to the inclination and the surface is the hypotenuse.
An eye sees the top of a vertical tower at elevation 27.0∘27.0^\circ27.0∘ and its base at depression 18.0∘18.0^\circ18.0∘. Both angles use the eye's horizontal in a common vertical plane. The horizontal run is 35.035.035.0 m. Find whole tower height to the nearest tenth.
The horizontal through the eye divides the tower into two parts on opposite sides of that line.
An observer stands on ground 2.02.02.0 m below the base level of a vertical tower. The eye is 1.71.71.7 m above the observer's ground. Horizontal run is 40.040.040.0 m and elevation is 36.0∘36.0^\circ36.0∘ in one vertical plane. Find tower height to the nearest tenth.
Relative to the tower base, the eye is 0.3 m below it. The sight rise must be reduced by that amount to obtain tower height.
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