Fun Math Challenge: Can You Find the Diameter?

Can you find the diameter of the largest semicircle? Pause and try it, then watch the whole solution built up one step at a time, ending back at the original picture. CHAPTERS 0:00 The puzzle 0:20 A first guess 0:35 The picture again 0:57 Cut the diameters in half 1:17 One straight line 2:01 A right triangle 2:45 Along the bottom 3:17 An angle in a half circle 3:42 Two triangles, one shape 5:06 Back to the picture