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Finding the Fourth Proportional to 78.47, 118.08 and 64.86

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Solution

The fourth proportional to 78.47, 118.08 and 64.86 is: 97.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.47 : 118.08 = 64.86 : x
  2. Step 2: Convert to fraction form
    78.47/118.08 = 64.86/x
  3. Step 3: Cross multiply
    78.47x = 118.08 × 64.86
  4. Step 4: Simplify right side
    78.47x = 7,658.67
  5. Step 5: Solve for x
    x = 7,658.67/78.47
  6. Step 6: Final answer
    x = 97.60

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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.