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Finding the Fourth Proportional to 421.78, 628.69 and 408.52

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Solution

The fourth proportional to 421.78, 628.69 and 408.52 is: 608.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.78 : 628.69 = 408.52 : x
  2. Step 2: Convert to fraction form
    421.78/628.69 = 408.52/x
  3. Step 3: Cross multiply
    421.78x = 628.69 × 408.52
  4. Step 4: Simplify right side
    421.78x = 256,832.44
  5. Step 5: Solve for x
    x = 256,832.44/421.78
  6. Step 6: Final answer
    x = 608.93

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.