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Finding the Fourth Proportional to 79.16, 109.84 and 78.12

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Solution

The fourth proportional to 79.16, 109.84 and 78.12 is: 108.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.16 : 109.84 = 78.12 : x
  2. Step 2: Convert to fraction form
    79.16/109.84 = 78.12/x
  3. Step 3: Cross multiply
    79.16x = 109.84 × 78.12
  4. Step 4: Simplify right side
    79.16x = 8,580.70
  5. Step 5: Solve for x
    x = 8,580.70/79.16
  6. Step 6: Final answer
    x = 108.40

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.