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Finding the Fourth Proportional to 79.77, 109.35 and 78.36

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Solution

The fourth proportional to 79.77, 109.35 and 78.36 is: 107.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.77 : 109.35 = 78.36 : x
  2. Step 2: Convert to fraction form
    79.77/109.35 = 78.36/x
  3. Step 3: Cross multiply
    79.77x = 109.35 × 78.36
  4. Step 4: Simplify right side
    79.77x = 8,568.67
  5. Step 5: Solve for x
    x = 8,568.67/79.77
  6. Step 6: Final answer
    x = 107.42

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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.