3) Find the missing angle.

Solution:

In the given triangle, two sides are marked with equal tick marks, indicating they are equal in length. This means the triangle is isosceles.

In an isosceles triangle, the angles opposite the equal sides are equal. One angle is given as \(80^{\circ}\).

The sum of angles in a triangle is \(180^{\circ}\).

Let the two equal angles be \(x^{\circ}\).

\(x^{\circ} + x^{\circ} + 80^{\circ} = 180^{\circ}\)

\(2x^{\circ} = 180^{\circ} - 80^{\circ}\)

\(2x^{\circ} = 100^{\circ}\)

\(x^{\circ} = 50^{\circ}\)

Answer: The missing angles are 50° each.