Which of the following pairs of angles are not coterminal ? (A) 330°

1.	Which of the following pairs of angles are not coterminal ? (A) 330°, - 60° (B) 405°, - 675°(C) 1230°, - 930°(D) 450°, - 630°
Answer» (A) 330°, - 60° Here, 405° - (- 675°) = 1080° = 3(360°), 1230° - (- 930°) = 2160° = 6(360°), and 450° - (- 630°) = 1080° = 3(360°) ∴ the above paris of angles are co-terminal. Now, 330° - (- 60°) = 390° Since 390° is not a multiple of 360°. ∴ This pair of angles is not co-terminal.

Which of the following pairs of angles are not coterminal ? (A) 330°, - 60° (B) 405°, - 675°(C) 1230°, - 930°(D) 450°, - 630°

Answer»

(A) 330°, - 60°

Here, 405° - (- 675°) = 1080° = 3(360°),

1230° - (- 930°) = 2160° = 6(360°),

and 450° - (- 630°) = 1080° = 3(360°)

∴ the above paris of angles are co-terminal.

Now, 330° - (- 60°) = 390°

Since 390° is not a multiple of 360°.

∴ This pair of angles is not co-terminal.