Find the figure obtained after folding the given figure along the dotted line.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) →
Note: The given answer is as per the official NTA Answer Key. However, there seems to be a mistake in the question: the options draw the result in the lower half, as if the upper half were folded down, but that fold gives an upside-down triangle beside a circle with a vertical line, which is not there in any of the options. Option (2) is the figure got when the lower half is folded up, as explained below.
When a sheet is folded along a line, the folded half turns over: each figure on it is turned upside down (mirrored in the fold line) and lands on the matching place of the other half.
Folding the lower half up onto the upper half:
The upside-down triangle turns over into an upright triangle and falls on the upright triangle of the upper half, so one upright triangle is seen.
The half circle with its round side on the left keeps that shape when turned upside down and meets the half circle ‘D’ (round side on the right): together they make a circle with a vertical line through it.
If the upper half were folded down instead, the upright triangle would turn into an upside-down one and land on the lower triangle, giving an upside-down triangle beside the same circle. The star of Option (1) would need the triangle to slide down without turning over, which a fold never does.