The area will be where r is the length of the leash.
Step-by-step explanation:
The area of a circle is pi times the radius squared. One forth of that area is not available for the dog to run: its the corner of the house. so what's left is 3/4 of the area of the circle. (3/4)πr²
Since the length of the leash is not given in the question, no specific Area can be answered. Once that value is substituted for r, the actual area can be calculated.
The height is 26 miles. Multiply that by 2 which gets 52 and then subtract that from 84. That gives you 32 which means the sum of the lengths is 32/2 which is 16 miles