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Finding the Fourth Proportional to 139.01, 208.24 and 90.20

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Solution

The fourth proportional to 139.01, 208.24 and 90.20 is: 135.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.01 : 208.24 = 90.20 : x
  2. Step 2: Convert to fraction form
    139.01/208.24 = 90.20/x
  3. Step 3: Cross multiply
    139.01x = 208.24 × 90.20
  4. Step 4: Simplify right side
    139.01x = 18,783.54
  5. Step 5: Solve for x
    x = 18,783.54/139.01
  6. Step 6: Final answer
    x = 135.13

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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.