Two equilateral triangles sharing a vertex and three line segments. Prove that the red triangle is isosceles.
Categories
The gate
Tag: triangle
Categories
Crossing mountains
A rectangle with four line segments. What’s brown : blue?
Categories
Diamond life
Two equilateral triangles and one centre. What’s green : red?
Categories
The new normal
Two equilateral triangles are placed as shown. Their centres are connected as well as their intersection points. What’s the angle α?
Categories
The dirty thirties
A triangle containing a semicircle and a circular sector centred in the right vertex. What is blue : green?
Categories
Scratching the surface
Three tangent semicircles and two coloured triangles. What’s the proportion yellow : green?
Categories
To the core
A non-isosceles triangle with a red cevian and three line segments to a point on the cevian. Prove that this point is the incentre of the triangle.
Categories
The seventh bell
A regular hexagon shares a vertex with an equilateral triangle of area 7. What is the area of the hexagon?
A square contains a yellow right triangle with an area of 11. What is the square’s area?
Categories
The erratic spider
A square with several line segments. Prove that the blue ones are parallel.