 I label the two new points e and/.' With the help of this figure he then proceeds to the usual proof of the theorem that the area of a parallelogram is equal to the product of the base by the altitude, establishing the equality of certain lines and angles...  Second-year Mathematics for Secondary Schools - Page 341by Ernst Rudolph Breslich - 1916 - 348 pagesFull view - About this book
 | Thomas Tate (mathematical master.) - 1848 - 284 pages
...angle. Since a parallelogram is double the area of the triangle cut off by a diagonal, it follows that, the area of a parallelogram is equal to the product of the two adjacent sides by the sine of the included angle. EXAMPLES. Ex. 1. The two sides of a triangle... | |
 | Henry Bartlett Maglathlin - Arithmetic - 1869 - 332 pages
...TRIANGLES AND QUADRILATERALS. 416i By Geometry, may be proved, in relation to areas, the following 1. The area of a PARALLELOGRAM is equal to the product of the base by the altitude. MENSURATION. This has been shown to be the case with a rectangle (Art. 210), and that... | |
 | Henry Bartlett Maglathlin - Arithmetic - 1880 - 370 pages
...QUADRILATERALS. 416. By Geometry may be proved, in relation to areas, the following PRINCIPLES. 1. The area of a PARALLELOGRAM is equal to the product of the base by the altitude. What is a Quadrilateral * A Parallelogram 1 A Rectangle 1 A Rhomboid 1 A Rhombus"... | |
 | Henry Bartlett Maglathlin - Arithmetic - 1882 - 398 pages
...rhombus ABCD is equal to the rectangle EEC F of the same base and altitude (Art. 218). I—A f D HenC6> The area of a parallelogram is equal to the product of the base and altitude. 9. What is the area of a parallelogram whose base is 36 feet and altitude 15 feet ? 10. The... | |
 | Seth Thayer Stewart - Geometry - 1891 - 428 pages
...area of a rectangle is equal to the product of its base and altitude. PROPOSITION XIV. 353. Theorem : The area of a parallelogram is equal to the product of the base and altitude. Statement : Let S be any parallelogram. The area of S is equal to the product of its base... | |
 | American Institute of Instruction - Education - 1891 - 334 pages
...lead a child to find out for himself than to tell him. The old fashion of letting a child learn that the area of a parallelogram is equal to the product of the length by the breadth was an easy one for the teacher and gave the desired knowledge, but the gaining... | |
 | William James Milne - Arithmetic - 1892 - 440 pages
...sides which form an angle meet is called the Vertex. PRACTICAL MEASUREMENTS. We have just learned that the area of a parallelogram is equal to the product of the numbers expressing its base and altitude. It is evident that a diagonal of a parallelogram divides... | |
 | William Shaffer Hall - Measurement - 1893 - 88 pages
...find the area of a parallelogram when two adjacent sides and the included angle are given. [16] RULE: The area of a parallelogram is equal to the product of the two adjacent sides, multiplied by the sine of the included angle. Proof : The area of a parallelogram... | |
 | Henry B. Maglathlin - 1894 - 370 pages
...QUADRILATERALS. 416. By Geometry may be proved, in relation to areas, the following PRINCIPLES. 1. The area of a PARALLELOGRAM is equal to the product of the base by the altitude. This has been shown to be the case with a rectangle (Art. 210), and that it applies... | |
 | William Watson - Physics - 1896 - 264 pages
...of this rectangle is obtained by multiplying the base DC M B FIG. 18. by the height CE (p. 26). Thus the area of a parallelogram is equal to the product of the base (DC) into the perpendicular distance between the base and the opposite side (CE or FD). EXERCISE 24.... | |
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