80
They are the numbers that have more than two factors in them.
20
Infinitely many, since every number in that range is a square of some other number. There are 7 perfect square numbers.
1600 square feet 20 x 80 = 1600
23,29,31,37,41,43,47,53,59,61,67,71,73,79.
No, there aren't any square numbers between 70 and 80. From 70 to 80, no number has a perfect square root, so no square number exists between 70 to 80.
80
They are the numbers that have more than two factors in them.
60 and 80
There are 40 odd numbers between 20 and 100. Remember that an odd number is every second number. There are 80 numbers between 20 and 100, so there are 40 odd numbers and 40 even numbers.
It is: 80
20
Infinitely many, since every number in that range is a square of some other number. There are 7 perfect square numbers.
1600 square feet 20 x 80 = 1600
Every integer from 20 to 99 qualifies; therefore there are 99 - 19 or 80 such numbers.
If a square has a perimeter of 80 meters, then each side is 20 meters in length. (80/4 sides of a square=20) The area of a square is side2, so 20*20 equals 400. The area of a square that has a perimeter of 80 meters is 400 meters2.