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Finding the Fourth Proportional to 642.76, 961.98 and 385

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Solution

The fourth proportional to 642.76, 961.98 and 385 is: 576.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.76 : 961.98 = 385 : x
  2. Step 2: Convert to fraction form
    642.76/961.98 = 385/x
  3. Step 3: Cross multiply
    642.76x = 961.98 × 385
  4. Step 4: Simplify right side
    642.76x = 370,362.30
  5. Step 5: Solve for x
    x = 370,362.30/642.76
  6. Step 6: Final answer
    x = 576.21

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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.