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Finding the Fourth Proportional to 921.80, 1,380.85 and 458.18

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Solution

The fourth proportional to 921.80, 1,380.85 and 458.18 is: 686.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.80 : 1,380.85 = 458.18 : x
  2. Step 2: Convert to fraction form
    921.80/1,380.85 = 458.18/x
  3. Step 3: Cross multiply
    921.80x = 1,380.85 × 458.18
  4. Step 4: Simplify right side
    921.80x = 632,668.66
  5. Step 5: Solve for x
    x = 632,668.66/921.80
  6. Step 6: Final answer
    x = 686.34

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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.