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Finding the Fourth Proportional to 421.70, 632.45 and 147.78

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Solution

The fourth proportional to 421.70, 632.45 and 147.78 is: 221.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.70 : 632.45 = 147.78 : x
  2. Step 2: Convert to fraction form
    421.70/632.45 = 147.78/x
  3. Step 3: Cross multiply
    421.70x = 632.45 × 147.78
  4. Step 4: Simplify right side
    421.70x = 93,462.72
  5. Step 5: Solve for x
    x = 93,462.72/421.70
  6. Step 6: Final answer
    x = 221.64

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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.