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Finding the Fourth Proportional to 920.90, 1,381.50 and 458.70

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Solution

The fourth proportional to 920.90, 1,381.50 and 458.70 is: 688.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    920.90 : 1,381.50 = 458.70 : x
  2. Step 2: Convert to fraction form
    920.90/1,381.50 = 458.70/x
  3. Step 3: Cross multiply
    920.90x = 1,381.50 × 458.70
  4. Step 4: Simplify right side
    920.90x = 633,694.05
  5. Step 5: Solve for x
    x = 633,694.05/920.90
  6. Step 6: Final answer
    x = 688.12

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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.