Inventional Geometry |
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Common terms and phrases
acute angles acute triangle adjacent angles angle inscribed angles are called base angles central angle circumference Circumscribe a circle complementary angles Construct a quadrilateral Construct a right Construct a square Construct a triangle Construct an equilateral Construct an isosceles cube curved line Decagon degrees in angle Describe a circle diagonal diameter divide Draw a line draw a perpendicular Draw three lines Draw two circles Draw two lines drawn equidistant equilateral triangle Euclid Find the area find the perimeter fold given line given point given to find hypotenuse inches long INVENTIONAL GEOMETRY isosceles triangle line Fig line of centers middle point number of degrees obtuse angles octagon parallelogram pentagon perpendicular bisector protractor pupils radius rectangle regular polygon rhomboid rhombus right angle Fig right triangle ruler semicircle side 2 inches square inches straight line Supplementary Angles take their sum tangent circles three angles trapezoid triangle ABC vertex vertical angle zoid
Popular passages
Page 5 - To divide one fraction by another, invert the ' divisor, and proceed as in multiplication.
Page 41 - In a right triangle, the side opposite the right angle is called the hypotenuse and is the longest side.
Page 61 - A circle is a plane figure bounded by a curved line, all points of which are equidistant from a point within called the center (Fig.
Page 55 - An octagon is a polygon of eight sides. A decagon is a polygon of ten sides. A dodecagon is a polygon of twelve sides. An equilateral polygon is one all of whose sides are equal. An equiangular polygon is one all of whose angles are equal. A regular polygon is one all of whose angles are equal and all ?f whose sides are equal.
Page 59 - The formula states that the square of the hypotenuse of a right triangle is equal to the sum of the squares of the base and altitude.
Page 41 - Any side may, however, be taken as the base. In an isosceles triangle, the side which is not one of the equal sides is usually considered as the base.
Page 55 - Polygons are classified according to the number of sides. A triangle is a polygon of three sides. A quadrilateral is a polygon of four sides. A pentagon is a polygon of five sides, Fig.
Page 38 - J_ to the given line. .'. the construction gives the perpendicular to a given line at a given point in the line.
Page 70 - A' and Y. PZ is the required perpendicular. (Why ?) SECOND METHOD. Use a right triangle. 110. To bisect a given angle. From P as a center, with a convenient radius, describe an arc cutting the sides of the "angle at X and Y. Construct Z equidistant from X and Y. PZ bisects the given angle. (Why?) 111. To bisect a given arc. If 0 is the center of the arc AB, bisect the Z.AOB.