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Finding the Fourth Proportional to 102.86, 154.09 and 77.21

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Solution

The fourth proportional to 102.86, 154.09 and 77.21 is: 115.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.86 : 154.09 = 77.21 : x
  2. Step 2: Convert to fraction form
    102.86/154.09 = 77.21/x
  3. Step 3: Cross multiply
    102.86x = 154.09 × 77.21
  4. Step 4: Simplify right side
    102.86x = 11,897.67
  5. Step 5: Solve for x
    x = 11,897.67/102.86
  6. Step 6: Final answer
    x = 115.67

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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.