Solution Step 0/0
Using only a drafting triangle and a pencil it is possible to find the center of a circle.
How many times will you need to change the position of the drafting triangle to reach the goal? The initial placement is counted as the 1st change.
How many times will you need to change the position of the drafting triangle to reach the goal? The initial placement is counted as the 1st change.
Explanations
4 times.Place C, the right angle of the drafting triangle on the circumference, as is shown (1st change of the position). D and E, where triangle's legs cross the circumference, are the endpoints of a diameter. Draw it (2nd change).
Now get a second diameter the same way (3rd and 4th changes respectively).
The intersection of these two diameters is the center of the circle.
[After Boris A. Kordemsky. The Moscow Puzzles: 359 mathematical recreations. 1972]
Check 3
Check 4
Check 5
Check 6
