Plane Geometry |
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Page 14
... angle into four equal parts . 3. Divide a given angle into eight equal parts . 4. Can the process of bisecting an ... acute angle is an angle less than a right angle , as ∠k An obtuse angle is an angle greater than a right angle ...
... angle into four equal parts . 3. Divide a given angle into eight equal parts . 4. Can the process of bisecting an ... acute angle is an angle less than a right angle , as ∠k An obtuse angle is an angle greater than a right angle ...
Page 39
... acute angles . The proof is left to the student . 51. Corollary 3. — An exterior angle of any triangle is equal to the sum of the two opposite interior angles , and hence is greater than either one of them alone . SUGGESTION . - Prove ...
... acute angles . The proof is left to the student . 51. Corollary 3. — An exterior angle of any triangle is equal to the sum of the two opposite interior angles , and hence is greater than either one of them alone . SUGGESTION . - Prove ...
Page 40
... angle , and one of the acute angles is four times the other , how many degrees are there in each ? 12. In a certain triangle an exterior angle is twice the adjacent interior angle , and the two opposite interior angles are equal ...
... angle , and one of the acute angles is four times the other , how many degrees are there in each ? 12. In a certain triangle an exterior angle is twice the adjacent interior angle , and the two opposite interior angles are equal ...
Page 41
... angle of the triangle ? Then how many degrees are there in each angle which the ray makes with each mirror ? 18. If ... acute angles which have their sides perpendicular , PROOFS : PARALLEL AND PERPENDICULAR LINES 41.
... angle of the triangle ? Then how many degrees are there in each angle which the ray makes with each mirror ? 18. If ... acute angles which have their sides perpendicular , PROOFS : PARALLEL AND PERPENDICULAR LINES 41.
Page 42
... angle through the vertex , thus forming two acute angles . What is the relation between the acute angles ? What is the relation between each obtuse angle and the adja- cent acute angle ? 23. An acute angle and an obtuse angle which have ...
... angle through the vertex , thus forming two acute angles . What is the relation between the acute angles ? What is the relation between each obtuse angle and the adja- cent acute angle ? 23. An acute angle and an obtuse angle which have ...
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Common terms and phrases
ABCD AC and BC acute angle altitude angle equal angles are equal apothem base bisects central angle chord circle with center circumscribed compasses and straightedge Conclusion congruent Construct a triangle Corollary corresponding sides diagonals diameter distance Divide a given drawn equal angles equal arcs equal circles equilateral triangle EXERCISES exterior angles follows formed geometry given angle given circle given line given line-segment given point given triangle Hence hypotenuse Hypothesis inscribed angle intercepted internally tangent isosceles triangle locus measure medians middle points number of sides parallel lines parallelogram perimeter perpendicular bisector point of contact proof in full proof is left quadrilateral radii radius ratio rectangle regular polygon rhombus right angle right triangle secant segment Show similar polygons straight angle straight line student SUGGESTION tangent trapezoid triangle are equal vertex Write the proof Нур
Popular passages
Page 225 - ... they have an angle of one equal to an angle of the other and the including sides are proportional; (c) their sides are respectively proportional.
Page 76 - The straight line joining the middle points of two sides of a triangle is parallel to the third side and equal to half of it 46 INTERCEPTS BY PARALLEL LINES.
Page 132 - If two triangles have two sides of one equal respectively to two sides of the other, but the included angle of the first greater than the included angle of the second, then the third side of the first is greater than the third side of the second.
Page 53 - Two triangles are congruent if two sides and the included angle of one are equal respectively to two sides and the included angle of the other. 2. Two triangles are congruent if two angles and the included side of one are equal respectively to two angles and the included side of the other.
Page 4 - PERIPHERY of a circle is its entire bounding line ; or it is a curved line, all points of which are equally distant from a point within called the center.
Page 72 - There are three important theorems in geometry stating the conditions under which two triangles are congruent: 1. Two triangles are congruent if two sides and the included angle of one are equal respectively to two sides and the included angle of the other.
Page 260 - S' denote the areas of two circles, R and R' their radii, and D and D' their diameters. Then, I . 5*1 = =»!. That is, the areas of two circles are to each other as the squares of their radii, or as the squares of their diameters.
Page 199 - 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.
Page 203 - In any quadrilateral the sum of the squares of the four sides is equal to the sum of the squares of the diagonals, plus four times the square of the line joining the middle points of the diagonals.
Page 47 - In a right triangle, the side opposite the right angle is called the hypotenuse and is the longest side.