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Finding the Fourth Proportional to 421.15, 631.72 and 147.25

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Solution

The fourth proportional to 421.15, 631.72 and 147.25 is: 220.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.15 : 631.72 = 147.25 : x
  2. Step 2: Convert to fraction form
    421.15/631.72 = 147.25/x
  3. Step 3: Cross multiply
    421.15x = 631.72 × 147.25
  4. Step 4: Simplify right side
    421.15x = 93,020.77
  5. Step 5: Solve for x
    x = 93,020.77/421.15
  6. Step 6: Final answer
    x = 220.87

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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.