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Finding the Fourth Proportional to 305.39, 421.56 and 231.72

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Solution

The fourth proportional to 305.39, 421.56 and 231.72 is: 319.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.39 : 421.56 = 231.72 : x
  2. Step 2: Convert to fraction form
    305.39/421.56 = 231.72/x
  3. Step 3: Cross multiply
    305.39x = 421.56 × 231.72
  4. Step 4: Simplify right side
    305.39x = 97,683.88
  5. Step 5: Solve for x
    x = 97,683.88/305.39
  6. Step 6: Final answer
    x = 319.87

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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.