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Finding the Fourth Proportional to 79.36, 109.46 and 78.16

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Solution

The fourth proportional to 79.36, 109.46 and 78.16 is: 107.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.36 : 109.46 = 78.16 : x
  2. Step 2: Convert to fraction form
    79.36/109.46 = 78.16/x
  3. Step 3: Cross multiply
    79.36x = 109.46 × 78.16
  4. Step 4: Simplify right side
    79.36x = 8,555.39
  5. Step 5: Solve for x
    x = 8,555.39/79.36
  6. Step 6: Final answer
    x = 107.80

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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.