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Finding the Fourth Proportional to 99.85, 137.78 and 56.18

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Solution

The fourth proportional to 99.85, 137.78 and 56.18 is: 77.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.85 : 137.78 = 56.18 : x
  2. Step 2: Convert to fraction form
    99.85/137.78 = 56.18/x
  3. Step 3: Cross multiply
    99.85x = 137.78 × 56.18
  4. Step 4: Simplify right side
    99.85x = 7,740.97
  5. Step 5: Solve for x
    x = 7,740.97/99.85
  6. Step 6: Final answer
    x = 77.53

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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.