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Finding the Fourth Proportional to 98.39, 135.65 and 72.15

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Solution

The fourth proportional to 98.39, 135.65 and 72.15 is: 99.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.39 : 135.65 = 72.15 : x
  2. Step 2: Convert to fraction form
    98.39/135.65 = 72.15/x
  3. Step 3: Cross multiply
    98.39x = 135.65 × 72.15
  4. Step 4: Simplify right side
    98.39x = 9,787.15
  5. Step 5: Solve for x
    x = 9,787.15/98.39
  6. Step 6: Final answer
    x = 99.47

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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.