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Finding the Fourth Proportional to 211.39, 316.85 and 138.17

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Solution

The fourth proportional to 211.39, 316.85 and 138.17 is: 207.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.39 : 316.85 = 138.17 : x
  2. Step 2: Convert to fraction form
    211.39/316.85 = 138.17/x
  3. Step 3: Cross multiply
    211.39x = 316.85 × 138.17
  4. Step 4: Simplify right side
    211.39x = 43,779.16
  5. Step 5: Solve for x
    x = 43,779.16/211.39
  6. Step 6: Final answer
    x = 207.10

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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.