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Finding the Fourth Proportional to 212.18, 317.94 and 138.98

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Solution

The fourth proportional to 212.18, 317.94 and 138.98 is: 208.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.18 : 317.94 = 138.98 : x
  2. Step 2: Convert to fraction form
    212.18/317.94 = 138.98/x
  3. Step 3: Cross multiply
    212.18x = 317.94 × 138.98
  4. Step 4: Simplify right side
    212.18x = 44,187.30
  5. Step 5: Solve for x
    x = 44,187.30/212.18
  6. Step 6: Final answer
    x = 208.25

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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.