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Finding the Fourth Proportional to 139.35, 208.83 and 90.45

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Solution

The fourth proportional to 139.35, 208.83 and 90.45 is: 135.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.35 : 208.83 = 90.45 : x
  2. Step 2: Convert to fraction form
    139.35/208.83 = 90.45/x
  3. Step 3: Cross multiply
    139.35x = 208.83 × 90.45
  4. Step 4: Simplify right side
    139.35x = 18,888.67
  5. Step 5: Solve for x
    x = 18,888.67/139.35
  6. Step 6: Final answer
    x = 135.55

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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.