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Finding the Fourth Proportional to 138.16, 190.59 and 85.66

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Solution

The fourth proportional to 138.16, 190.59 and 85.66 is: 118.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.16 : 190.59 = 85.66 : x
  2. Step 2: Convert to fraction form
    138.16/190.59 = 85.66/x
  3. Step 3: Cross multiply
    138.16x = 190.59 × 85.66
  4. Step 4: Simplify right side
    138.16x = 16,325.14
  5. Step 5: Solve for x
    x = 16,325.14/138.16
  6. Step 6: Final answer
    x = 118.16

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.