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In any triangle, the square of the side opposite an acute angle is equal to the sum of the squares of the other two sides, minus twice the product of one of these sides and the projection of the other side upon it.
Yale University Entrance Examinations in Mathematics: 1884 to 1898 - Page 190
1898 - 208 pages

## Catalogue ...

Yale University. Sheffield Scientific School - 1905 - 1074 pages
...constructions. 2. In any triangle, the square of the side opposite an acute angle is equal to the sum of the squares of the other two sides, minus twice the...sides and the projection of the other side upon it. 3. The areas of two similar triangles are to each other as the squares of any two homologous sides....

## Plane and Spherical Trigonometry

James Morford Taylor - Trigonometry - 1905 - 256 pages
...about the triangle ABC. Law of cosines. In any triangle the square of any side is equal to the sum of the squares of the other two sides minus twice the product of these two sides into the cosine of their included angle. In figures 35 regard AD, DB, and A В as directed...

## Plane Geometry

Edward Rutledge Robbins - Geometry, Plane - 1906 - 268 pages
...346. THEOREM. In any triangle the square of the side opposite an acute angle is equal to the sum of the squares of the other two sides minus twice the product of one of these two sides and the projection of the other side upon that one. Given: (?). To Prove: c2=(?). Proof :...

## Plane Trigonometry

Daniel Alexander Murray - 1906 - 466 pages
...formulas can be expressed in words : In any triangle, the square of any side is equal to the sum of the squares of the other two sides minus twice the product of these two sides multiplied by the cosine of their included angle. NOTE. In Fig. 49 a, A is acute and...

## Geometry: Plane Trigonometry. Chain Surveying. Compass Surveying. Transit ...

International Correspondence Schools - Building - 1906 - 634 pages
...memory. 19. The Cosine Principle. — In any triangle, the square of one side is equal to the sum of the squares of the other two sides minus twice the product of these two sides and the cosine of their included angle. That is (Fig. 6), a' = f + c' - 2 bc cos A...

## Plane Trigonometry

Plane trigonometry - 1906 - 230 pages
...memory. 19. The Cosine Principle. — fn any triangle, the square of one side is equal to the sum of the squares of the other two sides minus twice the product of these two sides and the cosine ot their included angle. That is (Fig. 6), a' = b' + c' - 2 bc cos A...

## Plane and Solid Geometry

Edward Rutledge Robbins - Geometry - 1907 - 428 pages
...346. THEOREM. In any triangle the square of the side opposite an acute angle is equal to the sum of the squares of the other two sides minus twice the product of one of these two sides and the projection of the other side upon that one. Given: (?). To Prove: c2=(?). Proof:...

## New Plane and Solid Geometry

Webster Wells - Geometry - 1908 - 336 pages
...THEOREM 255. In any triangle, the square of the side opposite an acute angle is equal to the sum of the squares of the other two sides, minus twice the...sides and the projection of the other side upon it. AA B C B Fio. 1. Fio. 2. Draw acute-angled A ABC ; draw also &ABC having an obtuse angle at B. Let...