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Finding the Fourth Proportional to 79.78, 109.47 and 79.01

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Solution

The fourth proportional to 79.78, 109.47 and 79.01 is: 108.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.78 : 109.47 = 79.01 : x
  2. Step 2: Convert to fraction form
    79.78/109.47 = 79.01/x
  3. Step 3: Cross multiply
    79.78x = 109.47 × 79.01
  4. Step 4: Simplify right side
    79.78x = 8,649.56
  5. Step 5: Solve for x
    x = 8,649.56/79.78
  6. Step 6: Final answer
    x = 108.42

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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.