The radius of the large circle would just be the diameter of one of the smaller circles, so 14 inches.
In order to solve this, we will need to find the area of the large circle and subtract the area of two smaller circles.
I'll be using pi as 3.14 for this.
Large Circle:
Smaller Circle:
Now we just simply subtract them.
615.44 - (2 * 153.86)
= 307.72 inches
You might've noticed that is exactly half of the area of the larger circle.
That's because if you halve the radius of a circle, you will get one fourth of original area.