UPSKILL MATH PLUS
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Figure-1
Figure 1(i) is the original position of the square. If it is rotated by \(90°\) about the centre \(O\), we get figure 1(ii). Now observe the position of the shape. Rotate the square again by \(90°\), and you get figure 1(iii). When the square completes four quarter turns, the square reaches Figure 1(v), which is similar to its original position, Figure 1(i). You can check the coordinates of the square after each turn and note the number of turns it is taking to come to its original position.
Thus, We can see the square (EFHG) has rotational symmetry of order \(4\) about its centre \(O\).
(i) The centre of rotation is the centre of the shape marked as \(O\).
(ii) The angle of rotation is 90°.
(iii) The direction of rotation is clockwise.
(iv) The order of rotational symmetry is \(4\).
Figure-2
Figure 2(i) is the original position of the star. If it is rotated by \(72°\) about the centre \(O\), we get figure 2(ii). Now observe the position of the star. Rotate the star again by \(72°\), and you get figure 2(iii). When the star completes five turns, the star reaches figure 2(vi) which is similar to its original position figure 2(i). You can check the coordinates of the star after each turn and note the number of turns it is taking to come to its original position.
Thus, We can see the star (PQRST) has rotational symmetry of order \(5\) about its centre \(O\).
(i) The centre of rotation is the centre of the shape marked as \(O\).
(ii) The angle of rotation is 72°.
(iii) The direction of rotation is clockwise.
(iv) The order of rotational symmetry is \(5\).
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