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Finding the Fourth Proportional to 305.40, 420.38 and 231.54

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Solution

The fourth proportional to 305.40, 420.38 and 231.54 is: 318.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.40 : 420.38 = 231.54 : x
  2. Step 2: Convert to fraction form
    305.40/420.38 = 231.54/x
  3. Step 3: Cross multiply
    305.40x = 420.38 × 231.54
  4. Step 4: Simplify right side
    305.40x = 97,334.79
  5. Step 5: Solve for x
    x = 97,334.79/305.40
  6. Step 6: Final answer
    x = 318.71

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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.