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Finding the Fourth Proportional to 98.56, 135.96 and 78.87

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Solution

The fourth proportional to 98.56, 135.96 and 78.87 is: 108.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.56 : 135.96 = 78.87 : x
  2. Step 2: Convert to fraction form
    98.56/135.96 = 78.87/x
  3. Step 3: Cross multiply
    98.56x = 135.96 × 78.87
  4. Step 4: Simplify right side
    98.56x = 10,723.38
  5. Step 5: Solve for x
    x = 10,723.38/98.56
  6. Step 6: Final answer
    x = 108.80

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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.