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Finding the Fourth Proportional to 426.16, 638.70 and 421.57

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Solution

The fourth proportional to 426.16, 638.70 and 421.57 is: 631.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.16 : 638.70 = 421.57 : x
  2. Step 2: Convert to fraction form
    426.16/638.70 = 421.57/x
  3. Step 3: Cross multiply
    426.16x = 638.70 × 421.57
  4. Step 4: Simplify right side
    426.16x = 269,256.76
  5. Step 5: Solve for x
    x = 269,256.76/426.16
  6. Step 6: Final answer
    x = 631.82

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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.