GeometryDifficulty 1.3Find the answerCEMC Pascal · Canada · 2014
In the diagram, a figure is formed dividing a square into eight identical pieces using its two diagonals and the two lines joining the midpoints of opposite sides, and then drawing a circle in the square as shown.
This figure is reflected in line L. Which of the following shows the final position of the figure?
The square, its 8 pieces and 2 diagonals are symmetrical about line L.
Upon reflection, the circle moves from the triangular above L which is adjacent to and above the second diagonal to the triangular region below L which is adjacent to and above the second diagonal.
[[IMAGE0]]
Solution 2
We can see that the final position of the figure is given in (D) by first rotating the original figure by 45∘ clockwise to obtain: [[IMAGE1]] Then, reflecting the figure through the now vertical line, we obtain: [[IMAGE2]] When we reposition the figure and line back to the original position (by rotating counterclockwise by 45∘), we obtain the figure in (D).