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Finding the Fourth Proportional to 212.49, 318.12 and 130.78

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Solution

The fourth proportional to 212.49, 318.12 and 130.78 is: 195.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.49 : 318.12 = 130.78 : x
  2. Step 2: Convert to fraction form
    212.49/318.12 = 130.78/x
  3. Step 3: Cross multiply
    212.49x = 318.12 × 130.78
  4. Step 4: Simplify right side
    212.49x = 41,603.43
  5. Step 5: Solve for x
    x = 41,603.43/212.49
  6. Step 6: Final answer
    x = 195.79

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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.