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Finding the Fourth Proportional to 642.85, 887.15 and 380.87

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Solution

The fourth proportional to 642.85, 887.15 and 380.87 is: 525.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.85 : 887.15 = 380.87 : x
  2. Step 2: Convert to fraction form
    642.85/887.15 = 380.87/x
  3. Step 3: Cross multiply
    642.85x = 887.15 × 380.87
  4. Step 4: Simplify right side
    642.85x = 337,882.48
  5. Step 5: Solve for x
    x = 337,882.48/642.85
  6. Step 6: Final answer
    x = 525.60

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.