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Finding the Fourth Proportional to 102.69, 153.78 and 79.90

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Solution

The fourth proportional to 102.69, 153.78 and 79.90 is: 119.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.69 : 153.78 = 79.90 : x
  2. Step 2: Convert to fraction form
    102.69/153.78 = 79.90/x
  3. Step 3: Cross multiply
    102.69x = 153.78 × 79.90
  4. Step 4: Simplify right side
    102.69x = 12,287.02
  5. Step 5: Solve for x
    x = 12,287.02/102.69
  6. Step 6: Final answer
    x = 119.65

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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.