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Finding the Fourth Proportional to 987.90, 1,481.40 and 338.18

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Solution

The fourth proportional to 987.90, 1,481.40 and 338.18 is: 507.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.90 : 1,481.40 = 338.18 : x
  2. Step 2: Convert to fraction form
    987.90/1,481.40 = 338.18/x
  3. Step 3: Cross multiply
    987.90x = 1,481.40 × 338.18
  4. Step 4: Simplify right side
    987.90x = 500,979.85
  5. Step 5: Solve for x
    x = 500,979.85/987.90
  6. Step 6: Final answer
    x = 507.12

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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.