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Finding the Fourth Proportional to 78.64, 107.94 and 74.56

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Solution

The fourth proportional to 78.64, 107.94 and 74.56 is: 102.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.64 : 107.94 = 74.56 : x
  2. Step 2: Convert to fraction form
    78.64/107.94 = 74.56/x
  3. Step 3: Cross multiply
    78.64x = 107.94 × 74.56
  4. Step 4: Simplify right side
    78.64x = 8,048.01
  5. Step 5: Solve for x
    x = 8,048.01/78.64
  6. Step 6: Final answer
    x = 102.34

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.