Here are five angles marked on a
grid of squares. Write the letters of the angles
that are obtuse. Write the letters of the angles
that are acute.
The question asks us to find the
obtuse angles and the acute angles. Obtuse angles measure more than 90
degrees or more than a right angle but less than a straight line. And acute angles measure less than
90 degrees or less than a right angle. To help work out if the angles on
the grid are obtuse or acute, we could mark on 90 degrees and compare this to the
size of the angle.
We can see that angle 𝐴 measures
less than 90 degrees. So it’s an acute angle. Angle 𝐵 is a right angle. So it’s neither obtuse nor
acute. Angle 𝐶 measures more than 90
degrees or more than a right angle. So 𝐶 is an obtuse angle. Angle 𝐷 measures less than 90
degrees. So it’s an acute angle. Angle 𝐸 measures just more than 90
degrees. So it’s obtuse. The obtuse angles are angles 𝐶 and
𝐸. And the acute angles or the angles
which measure less than 90 degrees are angles 𝐴 and 𝐷.