By knowing the measurement of the angle.
A sextant, possibly.
A protractor.
The device that astronomers use to find the angle between the horizon and stars in the sky is called a sextant.
Means a device which measures the angle of the boom relative to horizontal. Enable to determine measurements to a precision degree.
boom stop
clinometer is the device which measures angle w.r.t to gravity
Such a device is known as a protractor.
consider a right angle triangle ABC with AB is the base BC is the height , assume that BC is the height of the hillfind the length ABfind the angle BACuse the above equationBC= (tan BAC) * ABso BC is the height of the hill
stokes basket stretcher
A protractor is a device for measuring the angle between two intersecting lines.http://en.wikipedia.org/wiki/ProtractorIt is a half circle and (most) have a pointer in the middle to help you see the angle you are going to use .
It device used by an engineer for drawing parallel lines,lanes in some angle etc.It is used in engineering graphics.
You should use a special device for measuring angles - a protractor. With a ruler, it is much more complicated, but still possible: you can mark two points on the angle, one on each side; measure the distance from the vertext of the angle to those points; measure the distance between the points; then use the Law of Cosines to calculate the angle.