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Finding the Fourth Proportional to 78.81, 108.67 and 51.17

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Solution

The fourth proportional to 78.81, 108.67 and 51.17 is: 70.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.81 : 108.67 = 51.17 : x
  2. Step 2: Convert to fraction form
    78.81/108.67 = 51.17/x
  3. Step 3: Cross multiply
    78.81x = 108.67 × 51.17
  4. Step 4: Simplify right side
    78.81x = 5,560.39
  5. Step 5: Solve for x
    x = 5,560.39/78.81
  6. Step 6: Final answer
    x = 70.55

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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.