 | Charles H. Gleason, Charles Benajah Gilbert - 1910 - عدد الصفحات: 288
...previous lessons, the following rules for finding the areas of plane figures have been learned : 1. The area of a triangle is equal to | the product of the base by the altitude. 2. The area of a rectangle is equal to the product of the length by the breadth. 3. The... | |
 | 1903 - عدد الصفحات: 886
...square measure were explained in the February, March, April and May (1902) Magazines. Prop. XIX. — The area of a triangle is equal to the product of the base multiplied by half the altitude. (In Fig. 20 suppose the altitude ad of the equilateral triangle abc... | |
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... the same thing, the product of one side by half the other. Moreover, since any triangle whatever is equal to a right-angled triangle of the same base and altitude (Geom. 170), we can make use of the following simple rule, where the known parts admit... 
