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Finding the Fourth Proportional to 311.78, 429.86 and 228.74

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Solution

The fourth proportional to 311.78, 429.86 and 228.74 is: 315.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.78 : 429.86 = 228.74 : x
  2. Step 2: Convert to fraction form
    311.78/429.86 = 228.74/x
  3. Step 3: Cross multiply
    311.78x = 429.86 × 228.74
  4. Step 4: Simplify right side
    311.78x = 98,328.08
  5. Step 5: Solve for x
    x = 98,328.08/311.78
  6. Step 6: Final answer
    x = 315.38

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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.