Measurement (area & perimeter): Rock Nests
The Problem
River chub live in the Mississippi River. In one area, on the riverbed, their rock-pile nests have a diameter of 1 m. The stretch of river is 21 m long and 11 m wide.
There is a minimum gap of 1 m between each rock-pile nest and a minimum gap of 1 m between each nest and the river bank.
1) What is the area of the riverbed on this stretch of river?
2) How many rock-pile nests can fit within this area?
3) What is the approximate area taken up by the rock-pile nests?
4) What is the approximate area of the riverbed that is not covered by rock-pile nests?
Note: Discuss why the word approximate has been used in questions 3 & 4.
Did you know?
The Mississippi River is the second longest river in North America, flowing 3,766 km from its source at Lake Itasca through the centre of the USA to the Gulf of Mexico.
Visualising the Problem and Getting Started
Jamal said, “If the riverbed was 11 m long and 7 m wide, there would be 15 nests.”
Do you agree with Jamal? How do you know?