A bent molecule XY₂ has a total dipole moment of 1.20 D.

Step 1. Half the angle. $\cos\dfrac{\theta}{2} = \dfrac{1.20}{2 \times 0.90} = 0.667$, so $\dfrac{\theta}{2} = 48.2^\circ$.

Step 2. The angle. $\theta = 96.4^\circ$.

Step 3. The limit. The largest possible total is $2 \times 0.90 = 1.80\ \text{D}$, when the two bonds point the same way. So $2.0\ \text{D}$ is impossible from these bonds alone.