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Finding the Fourth Proportional to 139.90, 193.04 and 77.72

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Solution

The fourth proportional to 139.90, 193.04 and 77.72 is: 107.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.90 : 193.04 = 77.72 : x
  2. Step 2: Convert to fraction form
    139.90/193.04 = 77.72/x
  3. Step 3: Cross multiply
    139.90x = 193.04 × 77.72
  4. Step 4: Simplify right side
    139.90x = 15,001.72
  5. Step 5: Solve for x
    x = 15,001.72/139.90
  6. Step 6: Final answer
    x = 107.23

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.