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Finding the Fourth Proportional to 821.40, 1,232.10 and 648.60

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Solution

The fourth proportional to 821.40, 1,232.10 and 648.60 is: 972.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.40 : 1,232.10 = 648.60 : x
  2. Step 2: Convert to fraction form
    821.40/1,232.10 = 648.60/x
  3. Step 3: Cross multiply
    821.40x = 1,232.10 × 648.60
  4. Step 4: Simplify right side
    821.40x = 799,140.06
  5. Step 5: Solve for x
    x = 799,140.06/821.40
  6. Step 6: Final answer
    x = 972.90

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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.