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Finding the Fourth Proportional to 139.28, 208.61 and 104.99

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Solution

The fourth proportional to 139.28, 208.61 and 104.99 is: 157.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.28 : 208.61 = 104.99 : x
  2. Step 2: Convert to fraction form
    139.28/208.61 = 104.99/x
  3. Step 3: Cross multiply
    139.28x = 208.61 × 104.99
  4. Step 4: Simplify right side
    139.28x = 21,900.40
  5. Step 5: Solve for x
    x = 21,900.40/139.28
  6. Step 6: Final answer
    x = 157.25

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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.