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Finding the Fourth Proportional to 105.39, 158.78 and 90.14

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Solution

The fourth proportional to 105.39, 158.78 and 90.14 is: 135.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.39 : 158.78 = 90.14 : x
  2. Step 2: Convert to fraction form
    105.39/158.78 = 90.14/x
  3. Step 3: Cross multiply
    105.39x = 158.78 × 90.14
  4. Step 4: Simplify right side
    105.39x = 14,311.86
  5. Step 5: Solve for x
    x = 14,311.86/105.39
  6. Step 6: Final answer
    x = 135.80

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.