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Finding the Fourth Proportional to 78.48, 116.78 and 77.67

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Solution

The fourth proportional to 78.48, 116.78 and 77.67 is: 115.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.48 : 116.78 = 77.67 : x
  2. Step 2: Convert to fraction form
    78.48/116.78 = 77.67/x
  3. Step 3: Cross multiply
    78.48x = 116.78 × 77.67
  4. Step 4: Simplify right side
    78.48x = 9,069.91
  5. Step 5: Solve for x
    x = 9,069.91/78.48
  6. Step 6: Final answer
    x = 115.58

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.