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Finding the Fourth Proportional to 139.95, 209.78 and 67.77

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Solution

The fourth proportional to 139.95, 209.78 and 67.77 is: 101.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.95 : 209.78 = 67.77 : x
  2. Step 2: Convert to fraction form
    139.95/209.78 = 67.77/x
  3. Step 3: Cross multiply
    139.95x = 209.78 × 67.77
  4. Step 4: Simplify right side
    139.95x = 14,215.40
  5. Step 5: Solve for x
    x = 14,215.40/139.95
  6. Step 6: Final answer
    x = 101.58

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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.