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Finding the Fourth Proportional to 21,312, 31,968 and 6,720

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Solution

The fourth proportional to 21,312, 31,968 and 6,720 is: 10,080

Step by Step Solution

  1. Step 1: Write the proportion equation
    21,312 : 31,968 = 6,720 : x
  2. Step 2: Convert to fraction form
    21,312/31,968 = 6,720/x
  3. Step 3: Cross multiply
    21,312x = 31,968 × 6,720
  4. Step 4: Simplify right side
    21,312x = 214,824,960
  5. Step 5: Solve for x
    x = 214,824,960/21,312
  6. Step 6: Final answer
    x = 10,080

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.