2011 CEMC Gauss (Grade 8) Problems/Problem 3

Problem

In the diagram, the value of $y$ is

$\text{ (A) }\ 60 \qquad\text{ (B) }\ 100\qquad\text{ (C) }\ 120\qquad\text{ (D) }\ 180\qquad\text{ (E) }\ 270$

One entire revolution is $360^{\circ}$ . As suggested by the diagram, the given part of the angle is $90^{\circ}$ . This means that we have:

$y^{\circ} + 90^{\circ} = 360^{\circ}$

Solving for y gives:

$y = \boxed {\textbf {(E) } 270}$

~anabel.disher