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Finding the Fourth Proportional to 139.48, 209.05 and 70.86

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Solution

The fourth proportional to 139.48, 209.05 and 70.86 is: 106.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.48 : 209.05 = 70.86 : x
  2. Step 2: Convert to fraction form
    139.48/209.05 = 70.86/x
  3. Step 3: Cross multiply
    139.48x = 209.05 × 70.86
  4. Step 4: Simplify right side
    139.48x = 14,813.28
  5. Step 5: Solve for x
    x = 14,813.28/139.48
  6. Step 6: Final answer
    x = 106.20

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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.