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Finding the Fourth Proportional to 211.38, 317.08 and 139.70

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Solution

The fourth proportional to 211.38, 317.08 and 139.70 is: 209.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.38 : 317.08 = 139.70 : x
  2. Step 2: Convert to fraction form
    211.38/317.08 = 139.70/x
  3. Step 3: Cross multiply
    211.38x = 317.08 × 139.70
  4. Step 4: Simplify right side
    211.38x = 44,296.08
  5. Step 5: Solve for x
    x = 44,296.08/211.38
  6. Step 6: Final answer
    x = 209.56

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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.