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Finding the Fourth Proportional to 99.95, 137.84 and 78.91

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Solution

The fourth proportional to 99.95, 137.84 and 78.91 is: 108.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.95 : 137.84 = 78.91 : x
  2. Step 2: Convert to fraction form
    99.95/137.84 = 78.91/x
  3. Step 3: Cross multiply
    99.95x = 137.84 × 78.91
  4. Step 4: Simplify right side
    99.95x = 10,875.87
  5. Step 5: Solve for x
    x = 10,875.87/99.95
  6. Step 6: Final answer
    x = 108.81

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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.