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Finding the Fourth Proportional to 642.78, 887.15 and 380.94

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Solution

The fourth proportional to 642.78, 887.15 and 380.94 is: 525.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.78 : 887.15 = 380.94 : x
  2. Step 2: Convert to fraction form
    642.78/887.15 = 380.94/x
  3. Step 3: Cross multiply
    642.78x = 887.15 × 380.94
  4. Step 4: Simplify right side
    642.78x = 337,950.92
  5. Step 5: Solve for x
    x = 337,950.92/642.78
  6. Step 6: Final answer
    x = 525.76

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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.