Q73Short answer
Draw the images P′, Q′ and R′ of the points P, n Q and R, respectively in the line n (Fig. 9.18). P Join P′ Q′ and Q′ R′ to form an angle P′ Q′ R′. Measure ∠PQR and ∠P′Q′R′. Are the two angles equal? Q Fig. 9.18
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