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Finding the Fourth Proportional to 79.40, 109.42 and 66.34

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Solution

The fourth proportional to 79.40, 109.42 and 66.34 is: 91.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.40 : 109.42 = 66.34 : x
  2. Step 2: Convert to fraction form
    79.40/109.42 = 66.34/x
  3. Step 3: Cross multiply
    79.40x = 109.42 × 66.34
  4. Step 4: Simplify right side
    79.40x = 7,258.92
  5. Step 5: Solve for x
    x = 7,258.92/79.40
  6. Step 6: Final answer
    x = 91.42

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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.