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Finding the Fourth Proportional to 981, 1,353.80 and 538.90

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Solution

The fourth proportional to 981, 1,353.80 and 538.90 is: 743.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    981 : 1,353.80 = 538.90 : x
  2. Step 2: Convert to fraction form
    981/1,353.80 = 538.90/x
  3. Step 3: Cross multiply
    981x = 1,353.80 × 538.90
  4. Step 4: Simplify right side
    981x = 729,562.82
  5. Step 5: Solve for x
    x = 729,562.82/981
  6. Step 6: Final answer
    x = 743.69

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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.