4. A rectangular back yard ice rink is to have an area of 1200m, and will be surrounded by boards. [6]
a) What are the dimensions of the ice rink that b) If one board is 2.0 m long, how many boards
9 can be enclosed for the least cost of boards? would you need to enclose the rink?

Step-by-step explanation:

We know that the ice rink is 1200 square meters, which means to enclose the rink we need dimensions of 20 meters by 60 meters, to have 1200 square meters of area.

Now, the boards are on the perimeter of the ice rink with dimensiosn 20 meters times 60 meters. So, its perimeter is

If each board is 2.0 meter long, that means we can divide to find the total number of boards we can have on the ice rink:

Therefore, with those dimensions, we can have 80 boards surrounding the ice rink.

the mistake in the pattern is that :

b. the decimal point was moved one too many place values each time

the correct pattern could be made by :

b. moving the decimal point to the right the same numbers of place values as the exponents