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Finding the Fourth Proportional to 78.60, 117.49 and 76.68

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Solution

The fourth proportional to 78.60, 117.49 and 76.68 is: 114.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.60 : 117.49 = 76.68 : x
  2. Step 2: Convert to fraction form
    78.60/117.49 = 76.68/x
  3. Step 3: Cross multiply
    78.60x = 117.49 × 76.68
  4. Step 4: Simplify right side
    78.60x = 9,009.13
  5. Step 5: Solve for x
    x = 9,009.13/78.60
  6. Step 6: Final answer
    x = 114.62

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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.