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Finding the Fourth Proportional to 311.39, 429.64 and 187.11

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Solution

The fourth proportional to 311.39, 429.64 and 187.11 is: 258.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.39 : 429.64 = 187.11 : x
  2. Step 2: Convert to fraction form
    311.39/429.64 = 187.11/x
  3. Step 3: Cross multiply
    311.39x = 429.64 × 187.11
  4. Step 4: Simplify right side
    311.39x = 80,386.86
  5. Step 5: Solve for x
    x = 80,386.86/311.39
  6. Step 6: Final answer
    x = 258.15

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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.