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Finding the Fourth Proportional to 78.91, 117.62 and 78.23

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Solution

The fourth proportional to 78.91, 117.62 and 78.23 is: 116.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.91 : 117.62 = 78.23 : x
  2. Step 2: Convert to fraction form
    78.91/117.62 = 78.23/x
  3. Step 3: Cross multiply
    78.91x = 117.62 × 78.23
  4. Step 4: Simplify right side
    78.91x = 9,201.41
  5. Step 5: Solve for x
    x = 9,201.41/78.91
  6. Step 6: Final answer
    x = 116.61

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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.