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Finding the Fourth Proportional to 421.18, 631.78 and 147.28

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Solution

The fourth proportional to 421.18, 631.78 and 147.28 is: 220.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.18 : 631.78 = 147.28 : x
  2. Step 2: Convert to fraction form
    421.18/631.78 = 147.28/x
  3. Step 3: Cross multiply
    421.18x = 631.78 × 147.28
  4. Step 4: Simplify right side
    421.18x = 93,048.56
  5. Step 5: Solve for x
    x = 93,048.56/421.18
  6. Step 6: Final answer
    x = 220.92

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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.