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Finding the Fourth Proportional to 311.95, 430.21 and 187.55

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Solution

The fourth proportional to 311.95, 430.21 and 187.55 is: 258.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.95 : 430.21 = 187.55 : x
  2. Step 2: Convert to fraction form
    311.95/430.21 = 187.55/x
  3. Step 3: Cross multiply
    311.95x = 430.21 × 187.55
  4. Step 4: Simplify right side
    311.95x = 80,685.58
  5. Step 5: Solve for x
    x = 80,685.58/311.95
  6. Step 6: Final answer
    x = 258.65

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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.