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Finding the Fourth Proportional to 99.90, 137.48 and 84.18

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Solution

The fourth proportional to 99.90, 137.48 and 84.18 is: 115.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.90 : 137.48 = 84.18 : x
  2. Step 2: Convert to fraction form
    99.90/137.48 = 84.18/x
  3. Step 3: Cross multiply
    99.90x = 137.48 × 84.18
  4. Step 4: Simplify right side
    99.90x = 11,573.07
  5. Step 5: Solve for x
    x = 11,573.07/99.90
  6. Step 6: Final answer
    x = 115.85

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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.