Stuck on problem

Question

3. A rectangle has a length of sqrt(171) and a width of sqrt(51) . What is the best estimate for its area?

Answer 1

Area = Length times Width

= sqr171 x sqr51

= sqr(171x51) = about 93.39 units squared

93.39 = about 100

100^2 = 1,000

171 = a little more than about 170

51 = a little more than about 50

170x50 = 8500 = very roughly 1000

sqr1000= 100 = about 93.39

a rough estimate would have been 100 = Area

which is close to 93.39, within 7%