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Finding the Fourth Proportional to 212.66, 318.49 and 139.49

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Solution

The fourth proportional to 212.66, 318.49 and 139.49 is: 208.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.66 : 318.49 = 139.49 : x
  2. Step 2: Convert to fraction form
    212.66/318.49 = 139.49/x
  3. Step 3: Cross multiply
    212.66x = 318.49 × 139.49
  4. Step 4: Simplify right side
    212.66x = 44,424.23
  5. Step 5: Solve for x
    x = 44,424.23/212.66
  6. Step 6: Final answer
    x = 208.90

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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.