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Finding the Fourth Proportional to 920.87, 1,380.29 and 458.21

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Solution

The fourth proportional to 920.87, 1,380.29 and 458.21 is: 686.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    920.87 : 1,380.29 = 458.21 : x
  2. Step 2: Convert to fraction form
    920.87/1,380.29 = 458.21/x
  3. Step 3: Cross multiply
    920.87x = 1,380.29 × 458.21
  4. Step 4: Simplify right side
    920.87x = 632,458.65
  5. Step 5: Solve for x
    x = 632,458.65/920.87
  6. Step 6: Final answer
    x = 686.81

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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.