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Finding the Fourth Proportional to 78.69, 108.54 and 64.11

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Solution

The fourth proportional to 78.69, 108.54 and 64.11 is: 88.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.69 : 108.54 = 64.11 : x
  2. Step 2: Convert to fraction form
    78.69/108.54 = 64.11/x
  3. Step 3: Cross multiply
    78.69x = 108.54 × 64.11
  4. Step 4: Simplify right side
    78.69x = 6,958.50
  5. Step 5: Solve for x
    x = 6,958.50/78.69
  6. Step 6: Final answer
    x = 88.43

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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.