The Elements of Plane Geometry

ABCD adjacent angles altitude equal angle equal angle formed apothem base and altitude bisector bisects central angle centre chord circumference circumscribed Conclusion construct a triangle Consult Prop decagon diagonals diameter draw drawn perpendicular equal circles equilateral triangle exterior angle F Hypothesis Find the area find the length Find the locus find the number given circle given line given point given square given straight line given triangle homologous homologous sides hypotenuse inches inscribed regular isosceles triangle legs line joining lines are cut mean proportional median middle point number of degrees number of sides opposite sides parallel lines parallelogram perimeter perpendicular drawn point of contact point of intersection Problem produced prove Q.E.D. Proposition quadrilateral radii radius ratio regular hexagon regular polygon rhombus right angle SCHOLIUM secant segments subtended tangent Theorem transversal trapezoid triangle is equal vertex vertical angle