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Finding the Fourth Proportional to 99.20, 137.10 and 85.40

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Solution

The fourth proportional to 99.20, 137.10 and 85.40 is: 118.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.20 : 137.10 = 85.40 : x
  2. Step 2: Convert to fraction form
    99.20/137.10 = 85.40/x
  3. Step 3: Cross multiply
    99.20x = 137.10 × 85.40
  4. Step 4: Simplify right side
    99.20x = 11,708.34
  5. Step 5: Solve for x
    x = 11,708.34/99.20
  6. Step 6: Final answer
    x = 118.03

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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.