Category Archives: Geometry

3 squares; (b/x)^2 – (a/x)^2 = (c/x)^2 – (b/x)^2 = k

. . . geometry is the art of reasoning well from badly drawn figures; however, these figures, if they are not to deceive us, must satisfy certain conditions; the proportions may be grossly altered, but the relative positions of the … Continue reading

Posted in Geometry, Number Puzzles | Tagged | Leave a comment

Angles in a Triangle: 55, 15 and 110

    In a triangle, the angles opposite to sides   a,   b,   c   measure   55,   15   and   110,   respectively. Can you prove that   c^2 – a^2 = ab ?   … Continue reading

Posted in Geometry | Tagged , | Leave a comment

Area between three tangent circles?

3 circles of radius r such that all three are externally tangent, what is the area of the shape in the center in terms of r?                 What’s the area between three tangent circles?     Area … Continue reading

Posted in Geometry | Tagged , , | Leave a comment

Rectangle, Isosceles Triangle Inscribed In a Circle

    Inscribe a rectangle of base W and height H and an isosceles triangle of base W in a circle of radius one as shown. For what value of H do the rectangle and triangle have the same area? … Continue reading

Posted in Geometry | Tagged , , | 1 Comment