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Finding the Fourth Proportional to 138.93, 208.35 and 87.45

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Solution

The fourth proportional to 138.93, 208.35 and 87.45 is: 131.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.93 : 208.35 = 87.45 : x
  2. Step 2: Convert to fraction form
    138.93/208.35 = 87.45/x
  3. Step 3: Cross multiply
    138.93x = 208.35 × 87.45
  4. Step 4: Simplify right side
    138.93x = 18,220.21
  5. Step 5: Solve for x
    x = 18,220.21/138.93
  6. Step 6: Final answer
    x = 131.15

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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.