The angle on the cube answer is really bugging me. I understand the isoceles triangle answer but if it's a cube made of squares, why isn't the angle two bisections ie, 90 degrees?
if you join the two ends of the red lines so that if forms a triangle
then a moments reflection will reveal that the sides are equal ( all three equal and that means equilateral triangle ) and so the angle is 60'
I know it's 60 degrees . As I said, I do understand the answer.
But...is all the sides are squares, which they are, a diagonal line drawn from corner to corner would bisect thr right angle. Therefore, two bisections would add up to another right angle.
the hole in the doughnut q came up regularly in Phys A Level in the sixties.
If you heat a cartwheel rimmy thing to fit over a wooden cartwheel (!) well it was 50 y ago, then the radius expands linearly ( as well as the circumference, since they are linearly related )