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Finding the Fourth Proportional to 78.44, 117.70 and 42.42

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Solution

The fourth proportional to 78.44, 117.70 and 42.42 is: 63.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.44 : 117.70 = 42.42 : x
  2. Step 2: Convert to fraction form
    78.44/117.70 = 42.42/x
  3. Step 3: Cross multiply
    78.44x = 117.70 × 42.42
  4. Step 4: Simplify right side
    78.44x = 4,992.83
  5. Step 5: Solve for x
    x = 4,992.83/78.44
  6. Step 6: Final answer
    x = 63.65

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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.