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Finding the Fourth Proportional to 211.47, 317.07 and 139.11

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Solution

The fourth proportional to 211.47, 317.07 and 139.11 is: 208.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.47 : 317.07 = 139.11 : x
  2. Step 2: Convert to fraction form
    211.47/317.07 = 139.11/x
  3. Step 3: Cross multiply
    211.47x = 317.07 × 139.11
  4. Step 4: Simplify right side
    211.47x = 44,107.61
  5. Step 5: Solve for x
    x = 44,107.61/211.47
  6. Step 6: Final answer
    x = 208.58

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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.