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Finding the Fourth Proportional to 211.12, 316.56 and 82.78

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Solution

The fourth proportional to 211.12, 316.56 and 82.78 is: 124.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.12 : 316.56 = 82.78 : x
  2. Step 2: Convert to fraction form
    211.12/316.56 = 82.78/x
  3. Step 3: Cross multiply
    211.12x = 316.56 × 82.78
  4. Step 4: Simplify right side
    211.12x = 26,204.84
  5. Step 5: Solve for x
    x = 26,204.84/211.12
  6. Step 6: Final answer
    x = 124.12

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.