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Finding the Fourth Proportional to 421.08, 628.44 and 393.72

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Solution

The fourth proportional to 421.08, 628.44 and 393.72 is: 587.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.08 : 628.44 = 393.72 : x
  2. Step 2: Convert to fraction form
    421.08/628.44 = 393.72/x
  3. Step 3: Cross multiply
    421.08x = 628.44 × 393.72
  4. Step 4: Simplify right side
    421.08x = 247,429.40
  5. Step 5: Solve for x
    x = 247,429.40/421.08
  6. Step 6: Final answer
    x = 587.61

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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.