Machine-translated by Google. Questions are authored in English.
Top

Discussion

The difference of two complementary angles is 40°. If smaller of these angles is y, then the value of \((2y + 15^{\circ})\) is

  • A.45°
  • B.50°
  • C.55°
  • D.65°

Answer: D

The value of (2y + 15°) is 65°.

Complementary angles add up to 90°. Let the larger be a and the smaller y:

\[ \begin{aligned} a + y &= 90^{\circ},\ a - y = 40^{\circ} \\ y &= 25^{\circ} \\ 2y + 15^{\circ} &= 65^{\circ} \end{aligned} \]

The angles are 65° and 25°, and they do add to 90° and differ by 40°. Note that 2y + 15° happens to equal the larger angle, a useful check. Any other value of y breaks one of the two conditions, so 45°, 50° and 55° are wrong.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.