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Finding the Fourth Proportional to 98.45, 135.79 and 85.49

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Solution

The fourth proportional to 98.45, 135.79 and 85.49 is: 117.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.45 : 135.79 = 85.49 : x
  2. Step 2: Convert to fraction form
    98.45/135.79 = 85.49/x
  3. Step 3: Cross multiply
    98.45x = 135.79 × 85.49
  4. Step 4: Simplify right side
    98.45x = 11,608.81
  5. Step 5: Solve for x
    x = 11,608.81/98.45
  6. Step 6: Final answer
    x = 117.91

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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.