Fat fat boy wants to make a square using rectangular cards measuring 18cm by 21cm. What is the least number of cards needed?
Originally posted by aYexa:Fat fat boy wants to make a square using rectangular cards measuring 18cm by 21cm. What is the least number of cards needed?
Common Multiples of 18 : 18, 36, 54, 72, 90, 108,126, 144, 162, 180
Common Multiples of 21 : 21, 42, 63, 84,105,126, 147, 168, 189
126/ 18 = 7
126/ 21 = 6
Least number of cards = 7 X 6 = 42 cards
Hey wait.
The LCM is 126. But why must be divided by 6 and 7 then multiply?
Originally posted by aYexa:Hey wait.
The LCM is 126. But why must be divided by 6 and 7 then multiply?
126 is divided by 18 to find the number of cards on one side, and divided by 21 again to find the number of cards on the perpendicular side.
With 6 cards in one row, and 7 cards in one column, we multiply the two together to find the number of cards in all.