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Finding the Fourth Proportional to 920.34, 1,380.78 and 487.80

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Solution

The fourth proportional to 920.34, 1,380.78 and 487.80 is: 731.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    920.34 : 1,380.78 = 487.80 : x
  2. Step 2: Convert to fraction form
    920.34/1,380.78 = 487.80/x
  3. Step 3: Cross multiply
    920.34x = 1,380.78 × 487.80
  4. Step 4: Simplify right side
    920.34x = 673,544.48
  5. Step 5: Solve for x
    x = 673,544.48/920.34
  6. Step 6: Final answer
    x = 731.84

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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.