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In any triangle, the square of a side opposite an acute angle is equal to the sum of the squares of the other two sides diminished by twice the product of one of those sides and the projection of the other side upon it.
Plane and Solid Geometry - Page 169
by Claude Irwin Palmer, Daniel Pomeroy Taylor - 1918 - 436 pages

## Plane Geometry

John Charles Stone, James Franklin Millis - Geometry - 1916 - 306 pages
...— In any obtuse triangle, the square of the side opposite the obtuse angle is equal to the sum of the squares of the other two sides plus twice the...one of those sides and the projection of the other upon it. Y~ Hypothesis. In A ABC, ZA is obtuse, a, b, and c are the sides opposite A, B, and C, respectively,...

## Plane Geometry

Edith Long, William Charles Brenke - Geometry, Modern - 1916 - 292 pages
...side opposite an acute angle is equal to the sum of the squares on the other two sides, diminished by twice the product of one of those sides and the projection of the other side upon it. Give the proof of this on the same plan as in the preceding theorem, noting that we now have c2 = h2...

## Plane Geometry

Edith Long, William Charles Brenke - Geometry, Modern - 1916 - 292 pages
...side opposite an acute angle is equal to the sum of the squares on the other two sides, diminished by twice the product of one of those sides and the projection of the other side upon it. Give the proof of this on the same plan as in the preceding theorem, noting that we now have c2 = h2...

## Plane Geometry

John Charles Stone, James Franklin Millis - Geometry - 1916 - 298 pages
...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 those sides and the projection of the other upon it. DB Hypothesis. — In A ABC, Z. A is acute, a, b, and e are the sides opposite A, B, and (7,...

## Plane and Solid Geometry

Webster Wells, Walter Wilson Hart - Geometry - 1916 - 504 pages
...triangle having an obtuse angle, the square of the side opposite the obtuse angle is equal to the sum of the squares of the other two sides, plus twice the product of one of these sides and the projection of the other side upon it. A a Hypothesis. In A ABC, ZC is an obtuse...

## Plane and Solid Geometry

William Betz - Geometry - 1916 - 536 pages
...side opposite the obtuse angle is equal to the sum of the squares of the other two sides increased by twice the product of one of those sides and the projection of the other upon it. Given, in the triangle ABC, that p is the projection of the side b upon the side a, and that...

## Third-year Mathematics for Secondary Schools

Ernst Rudolph Breslich - Logarithms - 1917 - 408 pages
...side opposite the acute angle is equal to the sum of the squares of the other two sides diminished by twice the product of one of those sides and the projection of the A other upon it.) FIG. 79 Since b' = b cos A, it follows that a2 = b2+c2-26c cos A. This means that...

## Solid Geometry

Claude Irwin Palmer - Geometry, Solid - 1918 - 192 pages
...In any obtuse triangle, the square of the side opposite the obtuse angle is equivalent to the sum of the squares of the other two sides, plus twice the...sides and the projection of the other side upon it. § 381. Theorem. In any triangle, the square of a side opposite an acute angle is equivalent to the...