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Finding the Fourth Proportional to 421.85, 632.70 and 147.80

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Solution

The fourth proportional to 421.85, 632.70 and 147.80 is: 221.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.85 : 632.70 = 147.80 : x
  2. Step 2: Convert to fraction form
    421.85/632.70 = 147.80/x
  3. Step 3: Cross multiply
    421.85x = 632.70 × 147.80
  4. Step 4: Simplify right side
    421.85x = 93,509.90
  5. Step 5: Solve for x
    x = 93,509.90/421.85
  6. Step 6: Final answer
    x = 221.67

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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.