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Finding the Fourth Proportional to 139.30, 208.77 and 66.13

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Solution

The fourth proportional to 139.30, 208.77 and 66.13 is: 99.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.30 : 208.77 = 66.13 : x
  2. Step 2: Convert to fraction form
    139.30/208.77 = 66.13/x
  3. Step 3: Cross multiply
    139.30x = 208.77 × 66.13
  4. Step 4: Simplify right side
    139.30x = 13,805.96
  5. Step 5: Solve for x
    x = 13,805.96/139.30
  6. Step 6: Final answer
    x = 99.11

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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.