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Finding the Fourth Proportional to 78.93, 108.86 and 65.11

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Solution

The fourth proportional to 78.93, 108.86 and 65.11 is: 89.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.93 : 108.86 = 65.11 : x
  2. Step 2: Convert to fraction form
    78.93/108.86 = 65.11/x
  3. Step 3: Cross multiply
    78.93x = 108.86 × 65.11
  4. Step 4: Simplify right side
    78.93x = 7,087.87
  5. Step 5: Solve for x
    x = 7,087.87/78.93
  6. Step 6: Final answer
    x = 89.80

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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.