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Finding the Fourth Proportional to 311.79, 430.20 and 187.54

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Solution

The fourth proportional to 311.79, 430.20 and 187.54 is: 258.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.79 : 430.20 = 187.54 : x
  2. Step 2: Convert to fraction form
    311.79/430.20 = 187.54/x
  3. Step 3: Cross multiply
    311.79x = 430.20 × 187.54
  4. Step 4: Simplify right side
    311.79x = 80,679.71
  5. Step 5: Solve for x
    x = 80,679.71/311.79
  6. Step 6: Final answer
    x = 258.76

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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.