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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 diminished by twice the product of one of those sides and the projection of the other upon that side.
Schultze and Sevenoak's Plane and Solid Geometry - Page 192
by Arthur Schultze, Frank Louis Sevenoak - 1918 - 457 pages

## Biennial Report

Education - 1903 - 630 pages
...equiangular. 6. Prove : 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 diminished by twice the product of one of these sides and the projection of the other side upon it. 7. Prove : The area of a regular polygon...

## Elements of Plane and Solid Geometry

Alan Sanders - Geometry - 1903 - 392 pages
...THEOREM 659. In any triangle the square of a side opposite an acute angle is equivalent to the sum of the squares of the other two sides, diminished by twice the product of one of these sides and the projection of the oiher side upon it. b B Let ABC be a A in which BC lies opposite...

## Biennial Report, Superintendant of Public Instruction, State of Florida

Education - 1903 - 552 pages
...of the opposite angles. (b) Prove that the square of any side of a triangle is equal to the sum of the squares of the other two sides, diminished by twice the product of the two sides multiplied by the cosine of their included angle. 10 credits eaeh. 4. The angle of elevation...

## Plane and Solid Geometry

George Albert Wentworth - Geometry - 1904 - 496 pages
...THEOREM. 375. 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 diminished by twice the product of one of those sides by the projection of the other upon that side. D Fio. 1. Fio. 2. Let C be an acute angle of the triangle...

## Plane Geometry

Fletcher Durell - Geometry, Plane - 1904 - 382 pages
...THEOREM 349. In any oblique 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 by the projection of the other side upon it. Given acute ZC in A ABC, and DC the projection of the...

## Plane and Solid Geometry

Fletcher Durell - Geometry - 1911 - 553 pages
...349. In any oblique triangle, tlie 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 by the projection of the other side upon it. ADO Fig. 1 Given acute ZC in A ABC, and DC the projection...

## A Text-book of Euclid's Elements for the Use of Schools, Book 1

Euclid - Euclid's Elements - 1904 - 488 pages
...the sum of the squares on the sides containing the obtuse angle by twice the rectangle contained by one of those sides, and the projection of the other side upon it. The Enunciation of Prop. 12 thus stated should be carefully compared with that of Prop. 13. EUCLID-S...

## Plane and Solid Geometry

Isaac Newton Failor - Geometry - 1906 - 440 pages
...THEOREM 373 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, diminished by...sides and the projection of the other side upon it. Fig. 1 Fig. 2 HYPOTHESIS. In the A ABC, the / B is acute, and BD is the projection of AB upon BC. Let...