CBSE Class 7 Answered

(a) Let the triangle to be constructed be ABC,

where AB = 8 cm, BC = 3 cm and AC = 4 cm

Now, BC + AC = 3 + 4 = 7 cm

And AB = 8 cm

Therefore, BC + AC < AB.

That is the sum two sides is not greater than the third side.

Hence, the triangle cannot be constructed.

(b) Let the triangle to be constructed be XYZ

where XY = 9 cm, YZ = 5 cm and XZ = 4 cm

Now, YZ + XZ = 5 + 4 = 9 cm

And XY = 9 cm

Therefore, YZ + XZ = XY.

That is the sum two sides is not greater than the third side.

Hence, the triangle cannot be constructed.