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16 to the remaining edges of the pattern. Free-hand circles must be placed to indicate where the bends are to be made. Suitable notches are provided at the laps so that they will fit together at an angle of 90° at the bottom corners of the box.

A separate pattern must be drawn for the two ends of the box, as these are not included in the main pattern. Extension lines dropped from the end elevation will determine the length of the end pieces. The height of the end pieces can be taken either from the pictorial view in Fig. 21, or from the end elevation. A $$\scriptstyle{\frac{3}{16}}$$-inch hem must be added to the top of the end pattern as shown. The ends of the hem are notched slightly as indicated.

The over-all dimensions of the patterns should be put in as indicated by the question marks on the drawing. The end and front elevations are to be dimensioned as indicated in Figs. 22 and 23.

12. Related Mathematics on Galvanized Match Box.— Girth and Cut.—The "Girth" is the distance around the profile view. The "Cut" is the distance around the profile plus the laps or locks necessary to join the pieces of metal together.

Over-all Dimensions.—Dimensions showing the sizes of the blank pieces of metal required to "get out" the job should be placed upon every pattern. These are known as "over-all" dimensions, as they include both the pattern and the edges allowed. Dimension lines for this purpose are indicated on Fig. 24 by question marks.

Rectangle.—A rectangle is a flat surface bounded by four straight lines forming right angles at their points of meeting. Figures 20 and 24 are examples of rectangles. The area of a rectangle is equal to the length multiplied by the width.

Problem 2A.—Compute the over-all dimensions from Fig. 22. Check these answers by measuring the drawing, and place the correct figures on the over-all dimension lines of Figs. 24 and 25.

Problem 2B.—Find the area of Fig. 24 and also the area of Fig. 25. (Use over-all dimensions.)

Problem 2C.—Find the total area of the metal required to construct the box. (One body and two end pieces.)