Lesson 10 Rectangle functions
The questions below come from work by pupils in earlier TM 10 lessons.
1. Lynda says: ‘If I know the perimeter and one of the sides of the rectangle, I can work out the other side. I can even find the area! How can she do this?
2. A rectangle has a perimeter of 18 and a height of 0.5 (half). What is its length? What happens to the length as the height is made even smaller? Give some examples. What is the longest length that it can have?
3. Another rectangle has an area of 20 and a height of 0.5. What is its length? What happens to the length as the height is made smaller? What is the longest that the length can be?
4. Alan says: “If you want to measure the area of a rectangle in smaller size units than you first used, the answer is not simple.” What does he mean? Let us think about the problem:
Compare the number of square tiles with sides of one centimetre with the number of square tiles with sides of half a centimetre, that will cover the rectangle below (not to scale).
Number of tiles 1 cm x 1 cm ………
Number of tiles 1/2 cm x 1/2 cm ……..
Give your reasons for the difference in the answers.
How does this answer Alan’s statement?
not to scale