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Finding the Fourth Proportional to 138.93, 208.39 and 56.70

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Solution

The fourth proportional to 138.93, 208.39 and 56.70 is: 85.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.93 : 208.39 = 56.70 : x
  2. Step 2: Convert to fraction form
    138.93/208.39 = 56.70/x
  3. Step 3: Cross multiply
    138.93x = 208.39 × 56.70
  4. Step 4: Simplify right side
    138.93x = 11,814.53
  5. Step 5: Solve for x
    x = 11,814.53/138.93
  6. Step 6: Final answer
    x = 85.04

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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.