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Finding the Fourth Proportional to 212.86, 318.83 and 139.55

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Solution

The fourth proportional to 212.86, 318.83 and 139.55 is: 209.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.86 : 318.83 = 139.55 : x
  2. Step 2: Convert to fraction form
    212.86/318.83 = 139.55/x
  3. Step 3: Cross multiply
    212.86x = 318.83 × 139.55
  4. Step 4: Simplify right side
    212.86x = 44,492.03
  5. Step 5: Solve for x
    x = 44,492.03/212.86
  6. Step 6: Final answer
    x = 209.03

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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.