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Finding the Fourth Proportional to 981.71, 1,354.03 and 631.79

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Solution

The fourth proportional to 981.71, 1,354.03 and 631.79 is: 871.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    981.71 : 1,354.03 = 631.79 : x
  2. Step 2: Convert to fraction form
    981.71/1,354.03 = 631.79/x
  3. Step 3: Cross multiply
    981.71x = 1,354.03 × 631.79
  4. Step 4: Simplify right side
    981.71x = 855,462.61
  5. Step 5: Solve for x
    x = 855,462.61/981.71
  6. Step 6: Final answer
    x = 871.40

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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.