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Finding the Fourth Proportional to 138.74, 207.84 and 90.50

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Solution

The fourth proportional to 138.74, 207.84 and 90.50 is: 135.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.74 : 207.84 = 90.50 : x
  2. Step 2: Convert to fraction form
    138.74/207.84 = 90.50/x
  3. Step 3: Cross multiply
    138.74x = 207.84 × 90.50
  4. Step 4: Simplify right side
    138.74x = 18,809.52
  5. Step 5: Solve for x
    x = 18,809.52/138.74
  6. Step 6: Final answer
    x = 135.57

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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.