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Finding the Fourth Proportional to 139.78, 208.63 and 123.76

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Solution

The fourth proportional to 139.78, 208.63 and 123.76 is: 184.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.78 : 208.63 = 123.76 : x
  2. Step 2: Convert to fraction form
    139.78/208.63 = 123.76/x
  3. Step 3: Cross multiply
    139.78x = 208.63 × 123.76
  4. Step 4: Simplify right side
    139.78x = 25,820.05
  5. Step 5: Solve for x
    x = 25,820.05/139.78
  6. Step 6: Final answer
    x = 184.72

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.