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Finding the Fourth Proportional to 821.48, 1,229.90 and 655.38

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Solution

The fourth proportional to 821.48, 1,229.90 and 655.38 is: 981.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.48 : 1,229.90 = 655.38 : x
  2. Step 2: Convert to fraction form
    821.48/1,229.90 = 655.38/x
  3. Step 3: Cross multiply
    821.48x = 1,229.90 × 655.38
  4. Step 4: Simplify right side
    821.48x = 806,048.59
  5. Step 5: Solve for x
    x = 806,048.59/821.48
  6. Step 6: Final answer
    x = 981.21

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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.