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Finding the Fourth Proportional to 421.95, 631.48 and 385.43

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Solution

The fourth proportional to 421.95, 631.48 and 385.43 is: 576.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.95 : 631.48 = 385.43 : x
  2. Step 2: Convert to fraction form
    421.95/631.48 = 385.43/x
  3. Step 3: Cross multiply
    421.95x = 631.48 × 385.43
  4. Step 4: Simplify right side
    421.95x = 243,391.34
  5. Step 5: Solve for x
    x = 243,391.34/421.95
  6. Step 6: Final answer
    x = 576.83

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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.