Whether the following angles are acute, right or obtuse by measuring them with the tester.

Question

Take two match sticks and join them together at one end to create on L – shape. This is equal to a right angle. We will use it as a tester. As shown in figure keep the tester on the side AB of ∠AOB. Since, ∠AOB is smaller than right angle, it is acute angle. Again keep the tester on side QR of ∠PQR such that the corner of the tester coincides with point Q. Since, ∠PQR is bigger than right angle, it is an obtuse angle.

Whether the following angles are acute, right or obtuse by measuring them with the tester.

You measured and classified angles using the right angle tester in activity, into acute angle, right angle and obtuse angle. With a protractor measure and write the angles in the following table.

Answer 1

On measuring above angles by tester, we find that: 

1. Acute angle (i), (vi), (vii) 

2. Obtuse angle (ii), (ii), (v) 

3. Right angle (iv).

We find the following values of angles given in activity, by measuring them with a protractor. 

Measurements of acute angles : 

(i) 45° 

(vi) 30° 

(vii) 45° 

Measurements of Obtuse angles : 

(ii) 105° 

(iii) 120° 

(v) 135° 

Measurements of right angle : 

(iv) 90°