Question

Look at these figures.

1. How many angles are there in each?

2. Which of these can be drawn using set squares?

Answer 1

1. When two lines meet at a point, a corner is formed. The corner thus formed refers to an angle.

In the first figure, there are three corners. So, the figure has three angles.

In the second figure, there are four corners. So, the figure has four angles.

In the third figure, there are five corners. So, the figure has five angles.

In the fourth figure, there are six corners. So, the figure has six angles.

2. Using the set squares, we can draw angles of measures 30°, 45°, 60°, 90° and combination of these angles.

In the first figure, each angle measures 60°, which can be drawn using the set square.

Therefore, the first figure can be drawn using the set square.

In the second figure, each angle measures 90°, which can be drawn using the set square. Therefore, the second figure can be drawn using the set square.

In the third figure, each angle measures 110°, which cannot be drawn using the set square.

Therefore, the third figure cannot be drawn using the set square.

In the fourth figure, each angle measures 120°.

120° = 90° + 30°

As 90° and 30° angles can be drawn using the set square, therefore 120° angle can be drawn using the set square.

Therefore, the fourth figure can be drawn using the set square.