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Finding the Fourth Proportional to 305.60, 421.36 and 231.78

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Solution

The fourth proportional to 305.60, 421.36 and 231.78 is: 319.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.60 : 421.36 = 231.78 : x
  2. Step 2: Convert to fraction form
    305.60/421.36 = 231.78/x
  3. Step 3: Cross multiply
    305.60x = 421.36 × 231.78
  4. Step 4: Simplify right side
    305.60x = 97,663.82
  5. Step 5: Solve for x
    x = 97,663.82/305.60
  6. Step 6: Final answer
    x = 319.59

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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.