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Finding the Fourth Proportional to 99.45, 137.15 and 78.41

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Solution

The fourth proportional to 99.45, 137.15 and 78.41 is: 108.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.45 : 137.15 = 78.41 : x
  2. Step 2: Convert to fraction form
    99.45/137.15 = 78.41/x
  3. Step 3: Cross multiply
    99.45x = 137.15 × 78.41
  4. Step 4: Simplify right side
    99.45x = 10,752.85
  5. Step 5: Solve for x
    x = 10,752.85/99.45
  6. Step 6: Final answer
    x = 108.13

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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.