A right isosceles triangle contains another triangle. What is the angle α? Advanced if no trigonometry is used.
Tag: angle
The telescope
The odd regular polygons are stacked together, in increasing order, zigzagging to form a telescope that extends forever! What is the limiting angle (with respect to the horizontal) at which the telescope points?
The weight lifter
Express the x coordinate of E in terms of x coordinates of A, B, F, and G. The two black lines are supposed to be parallel to the x-axis.
Outside the pentagon
A regular pentagon and two coloured equilateral triangles. What is the angle α?
Baby block II
A square containing another square with an extended side. What is tan(α) in terms of the red and green segment lengths?
The boomerang
A quadrilateral and a triangle. What’s the angle α?
The pentagon proportion
A regular pentagon and a circular arc through its red centre. What’s the proportion α : β?
Baby steps
The edges of a cyclic quadrilateral extend to two intersections. O is the circle centre. The two diagonals intersect inside the circle. What is the angle α?
The party hat II
An equilateral triangle with a circular arc through its red centre and two vertices. If the yellow area equals the green one, what’s the angle α?
Tip of the veil
A square with two right angles. What fraction is yellow?