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Finding the Fourth Proportional to 98.75, 135.98 and 84.78

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Solution

The fourth proportional to 98.75, 135.98 and 84.78 is: 116.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.75 : 135.98 = 84.78 : x
  2. Step 2: Convert to fraction form
    98.75/135.98 = 84.78/x
  3. Step 3: Cross multiply
    98.75x = 135.98 × 84.78
  4. Step 4: Simplify right side
    98.75x = 11,528.28
  5. Step 5: Solve for x
    x = 11,528.28/98.75
  6. Step 6: Final answer
    x = 116.74

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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.