Page:An introduction to linear drawing.djvu/93

 ﻿height is unknown, but the diagonal (a right line drawn from corner to corner) is found by measurement to be 15 inches, 32 hundredths. What is the height ?

Note. A diagonal cuts the oblong square or rect- angle into two rectangular triangles, of which the height above required is one of the smaller sides.

8,54	15,32	As a smaller side is re-

8,54	15,32	quired, subtract the known

smaller from the larger.

3416	3064

4270	4596	234,7024

6832	7660	72,9316

1532	--

72,9316	161,7708

234,7024

It remains to find a number, which multiplied by it- self will give 161,770. A few trials will show that this is (as near as possible) 12,719 as may be found by multiplying this number by itself. The height then, is 12 inches, and 719 thousandths of an inch.

Example 3. Find the height of an isoceles triangle, (1st Class, Prob. 27.) whose base is 52 and the equal sides, 87. The perpendicular, drawn from the summit, cuts the base in halves, and is one side of a rectan- gular triangle, of which

the base i§ half the larger one, or. . 26 The great side of the new angle, which	26

was one of the equal sides of the	-

isoceles, is........ 87 156

87 52

From 7569	- -

Take 676	609 676

--696

6893	• -

7569