A property from geometry states that rectangles have congruent opposite sides. Thus, no matter which diagonal Reggie cuts, it still has the same lengths. Since it's a rectangle and we cut from corner to corner, we create a right triangle. See the picture below:
___________12 inches_______
7 |
i |
n |
Because it's a rectangle, it won't matter which corner we cut. But if we fold at the cut lines, we would make an in the rectangle's center.
The cut line and two sides make a right triangle. One leg is 12, one leg is 7, and we need to find the third side. The Pythagorean Theorem - sum of the squares of the legs equals the square of the hypotenuse - is applied.
Let S = the length of the side from corner to corner
S² = 12² + 7²
S² = 144 + 49
S² = 193
S = √193 or -√193
Because we are dealing with lengths, we only want positive numbers. -√193 is not used. Thus S = √193
S = √193 = 13.8924439894
S = 18.92 (rounded to two places)
Thus, Reggie will cut 18.92 inches of paper.
