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Finding the Fourth Proportional to 305.62, 421.78 and 231.80

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Solution

The fourth proportional to 305.62, 421.78 and 231.80 is: 319.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.62 : 421.78 = 231.80 : x
  2. Step 2: Convert to fraction form
    305.62/421.78 = 231.80/x
  3. Step 3: Cross multiply
    305.62x = 421.78 × 231.80
  4. Step 4: Simplify right side
    305.62x = 97,768.60
  5. Step 5: Solve for x
    x = 97,768.60/305.62
  6. Step 6: Final answer
    x = 319.90

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.