how can you use four rods that measure 2cm, 5cm, 7cm, and 9cm to measure a length of 1 cm?
( 5 + 7 ) - ( 9 + 2 ) = 12 - 11 = 1 cm
Put the 7cm and 5 cm rods together = 12 cm
Put the 9cm and 2cm rods together = 11 cm
Difference between is 1cm thus, you can use that difference to measure 1 cm.
Well, if you have those four rods of different lengths, you could simply toss them in a drawer and use a good old-fashioned ruler to measure that 1 cm length. No need to complicate things!
To measure a length of 1 cm using the given rods measuring 2 cm, 5 cm, 7 cm, and 9 cm, we can follow these steps:
Step 1: Place the 2 cm rod next to the 5 cm rod to form a length of 7 cm.
Step 2: Align the 7 cm rod with the 9 cm rod to create a length of 16 cm.
Step 3: Lay the 5 cm rod next to the 7 cm rod to obtain a length of 12 cm.
Step 4: Finally, place the 2 cm rod next to the 5 cm rod to achieve a length of 7 cm.
Now, by subtracting 6 cm from the length of 16 cm, we are left with a measurement of 1 cm.
To measure a length of 1 cm using rods of 2 cm, 5 cm, 7 cm, and 9 cm, you can follow these steps:
1. Begin by placing the 2 cm rod next to the length you want to measure. If the length is longer than 2 cm, move to the next step.
2. Remove the 2 cm rod and replace it with the 5 cm rod. Align one end of the 5 cm rod with the end of the length you want to measure. If the length is still longer than 5 cm, proceed to the next step.
3. Remove the 5 cm rod and replace it with the 7 cm rod. Align one end of the 7 cm rod with the end of the length you want to measure. If the length is still longer than 7 cm, continue to the next step.
4. Remove the 7 cm rod and replace it with the 9 cm rod. Align one end of the 9 cm rod with the end of the length you want to measure. If the length is still longer than 9 cm, move to the final step.
5. Take the 9 cm rod and place it alongside the length you want to measure. The length that remains uncovered by any of the rods is your desired measurement of 1 cm.
By using this method, you can measure any length up to 23 cm using the given rods. Keep in mind that this method assumes the rods can be placed end-to-end without any gaps.