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Finding the Fourth Proportional to 78.79, 108.58 and 76.43

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Solution

The fourth proportional to 78.79, 108.58 and 76.43 is: 105.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.79 : 108.58 = 76.43 : x
  2. Step 2: Convert to fraction form
    78.79/108.58 = 76.43/x
  3. Step 3: Cross multiply
    78.79x = 108.58 × 76.43
  4. Step 4: Simplify right side
    78.79x = 8,298.77
  5. Step 5: Solve for x
    x = 8,298.77/78.79
  6. Step 6: Final answer
    x = 105.33

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.