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Finding the Fourth Proportional to 78.36, 116.64 and 76.68

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Solution

The fourth proportional to 78.36, 116.64 and 76.68 is: 114.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.36 : 116.64 = 76.68 : x
  2. Step 2: Convert to fraction form
    78.36/116.64 = 76.68/x
  3. Step 3: Cross multiply
    78.36x = 116.64 × 76.68
  4. Step 4: Simplify right side
    78.36x = 8,943.96
  5. Step 5: Solve for x
    x = 8,943.96/78.36
  6. Step 6: Final answer
    x = 114.14

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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.