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Finding the Fourth Proportional to 981.72, 1,355.40 and 632.88

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Solution

The fourth proportional to 981.72, 1,355.40 and 632.88 is: 873.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    981.72 : 1,355.40 = 632.88 : x
  2. Step 2: Convert to fraction form
    981.72/1,355.40 = 632.88/x
  3. Step 3: Cross multiply
    981.72x = 1,355.40 × 632.88
  4. Step 4: Simplify right side
    981.72x = 857,805.55
  5. Step 5: Solve for x
    x = 857,805.55/981.72
  6. Step 6: Final answer
    x = 873.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.