The answer is A=68.142 inches
You have to add up all of the sides
I got 209 and I will attach a photo of my work.
The answer is Beryllium atom has a larger radius by 2 times.
Nitrogen atom: 5.6 × 10⁻¹¹ = 5.6 × 10⁻¹⁻¹⁰ = 5.6 × 10⁻¹ × 10⁻¹⁰ = 0.56 × 10⁻¹⁰
Beryllium atom: 1.12 × 10⁻¹⁰
Since 1.12 is bigger than 0.56, then the radius of beryllium atom is larger of the radius of nitrogen atom. Let's see by how many times:
1.12 × 10⁻¹⁰ : 0.56 × 10⁻¹⁰ = 1.12 : 0.56 = 2
