Problema Solution
Indiana Jones is standing on a large rock in the middle of a square pool filed with hungry, man-eating piranhas. The edge of the pool is 20 feet away from the rock. Indiana's mom wants to rescue her son, but she is standing on the edge of the pool with only two planks, 19 1/2 feet long. How can Indiana be rescued using the two planks?
Answer provided by our tutors
His Mom should lay one plank down across a corner of the pool, then the other plank can be laid down from the rock to the plank that cuts across the corner.
length of the pool's diagonal:
sqrt(20^2 + 20^2) = 28.3
a plank laid down so that the plank from the center squarely reaches the plank laid across the corner would cut that diagonal down to approximately 19 feet; a diagonal of 19 feet means sides of length 'x':
19 = sqrt(x^2 + x^2)
x = 13.43
the hypotenuse of a triangle with side 13.43 feet:
sqrt(13.43^2 + 13.43^2) = 18.9, less than the length of the 19.5 foot plank
so the planks are long enough to lay one down in such a way that it cuts the corner, allowing a plank from the rock to the diagonal plank - Indiana Jones can then run from the rock, to the diagonal plank, to the side of the pool and into the loving arms of his mother!