Answer:
216.97 X 10⁻⁵ N
Step-by-step explanation:
Charge q₁ and q₂ will attract q₃ with force F₁ and F₂ .F₁ and F₂ will be calculated as follows
F₁ =

F₁ = 82.01 X 10⁻⁵ N
F₂=

F₂ = 164.02 X 10⁻⁵ N
F₁ and F₂ will act at 60 degree so their resultant will be calculated as follows
R² = (82.01 X 10⁻⁵)² +( 164.02 X 10⁻⁵ )² + 2 X 82.01 X 164.02 X 10⁻¹⁰ Cos 60
R² = 47079.48 X 10⁻¹⁰
R = 216.97 X 10⁻⁵ N