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Finding the Fourth Proportional to 903.90, 1,355.36 and 318.85

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Solution

The fourth proportional to 903.90, 1,355.36 and 318.85 is: 478.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    903.90 : 1,355.36 = 318.85 : x
  2. Step 2: Convert to fraction form
    903.90/1,355.36 = 318.85/x
  3. Step 3: Cross multiply
    903.90x = 1,355.36 × 318.85
  4. Step 4: Simplify right side
    903.90x = 432,158.14
  5. Step 5: Solve for x
    x = 432,158.14/903.90
  6. Step 6: Final answer
    x = 478.10

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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.