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The area of a rectangle is equal to the product of its base and altitude. Given R a rectangle with base b and altitude a. To prove R = a X b. Proof. Let U be the unit of surface. .R axb U' Then 1x1 But - is the area of R.
A Treatise on Mensuration, Both in Theory and Practice - Page 91
by Charles Hutton - 1788 - 703 pages

## The Complete Arithmetic: Oral and Written

Daniel W. Fish - Arithmetic - 1874 - 516 pages
...of each rectangle. The units' figure of the root is equal to the width of one of these rectangles. The area of a rectangle is equal to the product of its length and width (462) ; hence, if the area be divided by the length, the quotient will be the width. Now, since...

## Elements of Geometry and Trigonometry: From the Works of A.M. Legendre

Adrien Marie Legendre - Geometry - 1874 - 455 pages
...rectangle AEGF will be the superficial unit, and we shall have, ABCD AB xAD ABCD = AB x AD : hence, the area of a rectangle is equal to the product of its base and altitude ; that is, the number of superficial units in the rectangle, is equal to the product...

## Euclid simplified, compiled from the most important French works

John Reynell Morell - 1875 - 16 pages
...explicit. L R a X 6 . a X b . — = — ^ — ; that is, — ^ — is the measure of the rectangle R. Therefore the area of a rectangle is equal to the product of its base by its height, divided by the second power of the side of the square, taken for unity ; the three...

## Manual of Geometry and Conic Sections: With Applications to Trigonometry and ...

William Guy Peck - Conic sections - 1876 - 366 pages
...B. 3) ; that is, = ~, or ACDE : KLMN :: AC : KL, AU which was to oe proved. PROPOSITION II. THEOREM. The area of a rectangle is equal to the product of its base and altitude. Let AD he a rectangle and AL the assumed superficial unit, that is, a square each...

## Complete Arithmetic: Theoretical and Practical

William Guy Peck - Arithmetic - 1877 - 341 pages
...is an expression for that surface in terms of a square unit. NOTE. — It is shown in geometry that the area of a rectangle is equal to the product of its length by its breadth ; that is, the number of square units in the surface is equal to the number of units...

## An Elementary Geometry: Plane, Solid, and Spherical : with Numerous ...

William Frothingham Bradbury - Geometry - 1877 - 240 pages
...to the square unit taken as a standard (29) as the product of its base by its altitude is to unity ; therefore the area of a rectangle is equal to the product of its base by its altitude, or to the product of its two dimensions. 41. Sch. I. 'By product of the base...

## Elements of Plane and Solid Geometry

George Albert Wentworth - Geometry - 1877 - 398 pages
...figures which have equal areas. R a' R a' S b V b GEOMETRY. BOOK IV. PROPOSITION III. THEOREM. 319. The area of a rectangle is equal to the product of its base and altitude. R bl Let R be the rectangle, b the base, and a the altitude ; and let U be a square...

## The Franklin Written Arithmetic, with Examples for Oral Practice

Edwin Pliny Seaver - 1878
...rectangle having the same base and height as the parallelogram, though we do not change the area. But the area of a rectangle is equal to the product of its base and height. Hence the Rule. To find the area of any parallelogram : Multiply the base by the height....