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Finding the Fourth Proportional to 78.81, 108.48 and 68.78

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Solution

The fourth proportional to 78.81, 108.48 and 68.78 is: 94.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.81 : 108.48 = 68.78 : x
  2. Step 2: Convert to fraction form
    78.81/108.48 = 68.78/x
  3. Step 3: Cross multiply
    78.81x = 108.48 × 68.78
  4. Step 4: Simplify right side
    78.81x = 7,460.71
  5. Step 5: Solve for x
    x = 7,460.71/78.81
  6. Step 6: Final answer
    x = 94.67

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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.