## Elements of Plane Trigonometry |

### From inside the book

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**radius*** . If U ° re- then by equation ( 1 ) , centre of a circle , the**radius**of the osition of the 6th Sentre of a circle which they stand , are IB : cir to the**radius**, 28 :: r : 2 #r :: D B being independent of r , is constant I ... Page 1

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**radius**which is called the circular measure of the angle . From equation ( 2 ) we see that the measuring unit , U , а must be multiplied by the fraction to find the angle ; - γ thus if the circular measure of an angle be 5 then , 10 5 A ... Page 2

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**radius**of the circle . πη Hence the length of the are of a quadrant is ; of a semi- 3πr circle , or 180 ° , is πr ; and of 270 ° , or three quadrants , is 2 Now if any arc a subtend an angle of 4o , then since πλ 2 subtends 90 ° , and ... Page 3

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**radius**and taking U as the unit , we have A ° = a r which is called the circular measure of the angle . From equation ( 2 ) we see that the measuring unit , U ° , а must be multiplied by the fraction to find the angle ; - r thus if the ... Page 5

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**radius**is 25 feet . 180 ° a A ° = X π 2 ' 180 ° 30 180 ° 6 X π 25 Π = 68 ° .75493 . 5 57 ° -29578 X 6 ( 6 ) Find the number of degrees in an angle of which the circular measure is 7854 , the value of being 3.1416 . 180 ° a 180 ° A ...### Other editions - View all

### Common terms and phrases

1+tan AB² AC² angle ACB AP AP AP AP² ARITHMETIC Asin Atan B+cot centre circular measure circumference cos² cos³ cosec cosine cot 4+cot cot A cot cot² OCA diameter distance equal equation Euclid feet Find the number formula given GRAMMAR height Hence hexagon inscribed circle IVY LANE J. R. Young King's College School log blog logarithms nth root number of degrees number of sides perimeter perpendicular plane triangle quadrant radii radius ratio regular polygon Rudimentary Treatise sec² shew sin A cos sin A sin sin¹ sin2 sin² 18 sin³ sine and cosine square subtend subtracted T. H. L. Leary tan-¹ tan² tangent triangle ABC Trigonometry unity VIRTUE BROTHERS W. D. Hamilton

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