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Finding the Fourth Proportional to 421.90, 628.15 and 421.90

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Solution

The fourth proportional to 421.90, 628.15 and 421.90 is: 628.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.90 : 628.15 = 421.90 : x
  2. Step 2: Convert to fraction form
    421.90/628.15 = 421.90/x
  3. Step 3: Cross multiply
    421.90x = 628.15 × 421.90
  4. Step 4: Simplify right side
    421.90x = 265,014.38
  5. Step 5: Solve for x
    x = 265,014.38/421.90
  6. Step 6: Final answer
    x = 628.15

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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.