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Finding the Fourth Proportional to 98.79, 136.28 and 76.65

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Solution

The fourth proportional to 98.79, 136.28 and 76.65 is: 105.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.79 : 136.28 = 76.65 : x
  2. Step 2: Convert to fraction form
    98.79/136.28 = 76.65/x
  3. Step 3: Cross multiply
    98.79x = 136.28 × 76.65
  4. Step 4: Simplify right side
    98.79x = 10,445.48
  5. Step 5: Solve for x
    x = 10,445.48/98.79
  6. Step 6: Final answer
    x = 105.73

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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.