The area of a square park is 81 km2. What is the time taken to complete a rotation at the speed of 5 km/h?
Answer & explanation
Correct answer: option 1
One rotation around the park = perimeter of square park
= 4 × side
= 4 × \(\sqrt {81}\) = 4 × 9
= 36 km
Time taken to complete this rotation = \(\frac{distance}{speed}\)
= \(\frac{36}{5}\)
= 7.2 hr
= 7 hr 12 min