1200 ÷ 16 1 12 = 74·61, the square root of which is 8·637, the time required.
When a body is projected vertically downwards with a given velocity, the space described is equal to the time multiplied by the velocity, together with the product of 16-1/12 by the square of the time; but, if the body is projected upwards, the latter product must be subtracted from the former.
PRACTICAL GEOMETRY.
DEFINITIONS.[55]
A line is perpendicular to another when it inclines not more on the one side than on the other, the angles on both sides being equal.
Parallel lines are those which have no inclination to each other, being everywhere equi-distant, however far produced, or extended.
An angle is the inclination, or opening of two lines, which meet in a point called the vertex, or angular point: and the two lines are called the legs, or sides of the angle.
The measure of an angle is estimated by the number of degrees contained in the arc between its two legs.
A rectilinear angle has its legs or sides, right, or straight lines.