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After remarking that the mathematician positively knows that the sum of the three angles of a triangle is equal to two right angles...
The New Practical Builder and Workman's Companion, Containing a Full Display ... - Σελίδα 28
των Peter Nicholson - 1823 - 596 σελίδες
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## An Introduction to Algebra: Being the First Part of a Course of Mathematics ...

Jeremiah Day - 1820 - 350 σελίδες
...equations, though they may not be presented to us under the algebraic forms. Thus the proposition, that the sum of the three angles of a triangle is equal to two right angles, (Euc. 32. 1.) may be demonstrated, either in common language, or by means of the signs used...

## Dictionary of the Mathematical and Physical Sciences, According to the ...

James Mitchell - 1823 - 670 σελίδες
...of a triangle is less than the sum, but greater than the difference of the other two sides. 3. Tlie sum of the three angles of a triangle is equal to two right angles; and the external angle formed by producing one of its sides is equal to the sum of the t\vu...

## An Introduction to Algebra: Being the First Part of a Course of Mathematics ...

Jeremiah Day - 1827 - 352 σελίδες
...equations, though they may not be presented to us under the algebraic forms. Thus the proposition, that the sum of the three angles of a triangle is equal to two right angles, (Euc. 32. 1.) may be demonstrated, either in common language, or by means of the signs used...

## Elements of the Geometry of Planes and Solids: With Four Plates

Ferdinand Rudolph Hassler - 1828 - 180 σελίδες
...of the line, which have been proved to be together, equal to two right angles; therefore, also, the sum of the three angles of a triangle is equal to two right angles; as was to be demonstrated. Carol. When two angles of a triangle are given, the third angle...

## Elements of Trigonometry, Plane and Spherical: Adapted to the Present State ...

Charles William Hackley - 1838 - 350 σελίδες
...and the other equal to 105° 30', it will be easy to find the third angle, by recollecting that the sum of the three angles of a triangle is equal to two right angles (Geom. B. 1, Prop. 25,) or 180° ; therefore subtracting the sum of the two given, 47° + 105°...

## A System of Crystallography, with Its Application to Mineralogy

John Joseph Griffin - 1841 - 548 σελίδες
...in any right-angled triangle, a either n or w be given, then n, c and w are all given ; because the sum of the three angles of a triangle is equal to two right angles. Hence: c = 90°; n = 00° — w ; and w = <JO° — • n. No. tiiven. Sought. Equations. Logarithmic...

## A System of Crystallography, with Its Application to Mineralogy

John Joseph Griffin - 1841 - 538 σελίδες
...in any right-angled triangle, either n or w. be given, then n, с and w are all given; because the sum of the three angles of a triangle is equal to two right angles. Hence: с = 90°; n = 90° — w ; and w = 90° — n. Т E.) OBLIQUE-ANGLED PLANE TRIANGLES....

## Elements of Plane Geometry: For the Use of Schools

Nicholas Tillinghast - 1844 - 110 σελίδες
...is the sum of the two angles CBE, EBD, is equal to the sum of the two angles BAC, BCA. Cor. 1 . The sum of the three angles of a triangle is equal to two right angles ; for CBD-f-CBA is equal to two right angles (Prop. 1) ; now we have just seen that CBD is equal...

## A Glance at the Physical Sciences; Or The Wonders of Nature,: In ..., Τόμος 1

Samuel Griswold Goodrich - 1844 - 370 σελίδες
...some property is asserted, and the truth of it required to be proved : thus when it is said that the sum of the three angles of a triangle is equal to two right angles, that is a theorem, the truth of which is demonstrated by geometry. A set, or collection, of...

## Elements of Algebra: Being an Abridgment of Day's Algebra, Adapted to the ...

James Bates Thomson - 1844 - 272 σελίδες
...equations, though they may not be presented to us under the algebraic forms. Thus the proposition, that the sum of the three angles of a triangle is equal to two right angles, (Euc. 32. 1,) may is' ' be demonstrated, either in common language, or by means of the signs...