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Finding the Fourth Proportional to 118.20, 162.78 and 85.40

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Solution

The fourth proportional to 118.20, 162.78 and 85.40 is: 117.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    118.20 : 162.78 = 85.40 : x
  2. Step 2: Convert to fraction form
    118.20/162.78 = 85.40/x
  3. Step 3: Cross multiply
    118.20x = 162.78 × 85.40
  4. Step 4: Simplify right side
    118.20x = 13,901.41
  5. Step 5: Solve for x
    x = 13,901.41/118.20
  6. Step 6: Final answer
    x = 117.61

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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.