- Maurice OReilly
Right triangle with given area, A, and perimeter, p
The area of the triangle is equal to that of the square. This can be adjusted by moving the red point. The perimeter of the triangle is the distance between the blue and orange points (comprising black, blue and pink segments). This can be adjusted by moving the orange point. The perimeter of the triangle must be at least the radius of the quadrant shown. Explore ... explain ... enjoy!
Adapted from Pyrgic puzzle by Chris Maslanka, The Guardian, 14 December 2019