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Finding the Fourth Proportional to 78.91, 108.94 and 49.85

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Solution

The fourth proportional to 78.91, 108.94 and 49.85 is: 68.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.91 : 108.94 = 49.85 : x
  2. Step 2: Convert to fraction form
    78.91/108.94 = 49.85/x
  3. Step 3: Cross multiply
    78.91x = 108.94 × 49.85
  4. Step 4: Simplify right side
    78.91x = 5,430.51
  5. Step 5: Solve for x
    x = 5,430.51/78.91
  6. Step 6: Final answer
    x = 68.82

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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.