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Finding the Fourth Proportional to 102.86, 154.20 and 91.40

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Solution

The fourth proportional to 102.86, 154.20 and 91.40 is: 137.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.86 : 154.20 = 91.40 : x
  2. Step 2: Convert to fraction form
    102.86/154.20 = 91.40/x
  3. Step 3: Cross multiply
    102.86x = 154.20 × 91.40
  4. Step 4: Simplify right side
    102.86x = 14,093.88
  5. Step 5: Solve for x
    x = 14,093.88/102.86
  6. Step 6: Final answer
    x = 137.02

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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.