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Finding the Fourth Proportional to 421.48, 578.81 and 391.42

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Solution

The fourth proportional to 421.48, 578.81 and 391.42 is: 537.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.48 : 578.81 = 391.42 : x
  2. Step 2: Convert to fraction form
    421.48/578.81 = 391.42/x
  3. Step 3: Cross multiply
    421.48x = 578.81 × 391.42
  4. Step 4: Simplify right side
    421.48x = 226,557.81
  5. Step 5: Solve for x
    x = 226,557.81/421.48
  6. Step 6: Final answer
    x = 537.53

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.