| 10 mm. | = | 1 | Centimeter | = | 0.3937 | inches. |
| 10 cm. | = | 1 | Decimeter | = | 3.937 | „ |
| 10 dm. | = | 1 | Meter | = | 39.37 | „ |
| 25.4 mm. | = | 1 English Inch. | ||||
RULES RELATIVE TO THE CIRCLE.
The circle contains a greater area than any other plane figure bounded by an equal perimeter or outline.
TO FIND CIRCUMFERENCE—
| Multiply diameter by | 3.1416. |
| Or divide diameter by | 0.3183. |
TO FIND DIAMETER—
| Multiply circumference by | 0.3183. |
| Or divide circumference by | 3.1416. |
TO FIND RADIUS—
| Multiply circumference by | 0.15915. |
| Or divide circumference by | 6.28318. |
TO FIND SIDE OF AN INSCRIBED SQUARE—