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Finding the Fourth Proportional to 78.76, 118.20 and 63.40

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Solution

The fourth proportional to 78.76, 118.20 and 63.40 is: 95.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.76 : 118.20 = 63.40 : x
  2. Step 2: Convert to fraction form
    78.76/118.20 = 63.40/x
  3. Step 3: Cross multiply
    78.76x = 118.20 × 63.40
  4. Step 4: Simplify right side
    78.76x = 7,493.88
  5. Step 5: Solve for x
    x = 7,493.88/78.76
  6. Step 6: Final answer
    x = 95.15

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.