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Finding the Fourth Proportional to 212.60, 318.90 and 140.78

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Solution

The fourth proportional to 212.60, 318.90 and 140.78 is: 211.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.60 : 318.90 = 140.78 : x
  2. Step 2: Convert to fraction form
    212.60/318.90 = 140.78/x
  3. Step 3: Cross multiply
    212.60x = 318.90 × 140.78
  4. Step 4: Simplify right side
    212.60x = 44,894.74
  5. Step 5: Solve for x
    x = 44,894.74/212.60
  6. Step 6: Final answer
    x = 211.17

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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.