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Finding the Fourth Proportional to 78.69, 108.62 and 54.19

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Solution

The fourth proportional to 78.69, 108.62 and 54.19 is: 74.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.69 : 108.62 = 54.19 : x
  2. Step 2: Convert to fraction form
    78.69/108.62 = 54.19/x
  3. Step 3: Cross multiply
    78.69x = 108.62 × 54.19
  4. Step 4: Simplify right side
    78.69x = 5,885.85
  5. Step 5: Solve for x
    x = 5,885.85/78.69
  6. Step 6: Final answer
    x = 74.80

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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.