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Finding the Fourth Proportional to 642.72, 886.90 and 380.70

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Solution

The fourth proportional to 642.72, 886.90 and 380.70 is: 525.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.72 : 886.90 = 380.70 : x
  2. Step 2: Convert to fraction form
    642.72/886.90 = 380.70/x
  3. Step 3: Cross multiply
    642.72x = 886.90 × 380.70
  4. Step 4: Simplify right side
    642.72x = 337,642.83
  5. Step 5: Solve for x
    x = 337,642.83/642.72
  6. Step 6: Final answer
    x = 525.33

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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.