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Finding the Fourth Proportional to 139.04, 208.55 and 66.88

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Solution

The fourth proportional to 139.04, 208.55 and 66.88 is: 100.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.04 : 208.55 = 66.88 : x
  2. Step 2: Convert to fraction form
    139.04/208.55 = 66.88/x
  3. Step 3: Cross multiply
    139.04x = 208.55 × 66.88
  4. Step 4: Simplify right side
    139.04x = 13,947.82
  5. Step 5: Solve for x
    x = 13,947.82/139.04
  6. Step 6: Final answer
    x = 100.32

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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.