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Finding the Fourth Proportional to 79.32, 109.40 and 61.88

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Solution

The fourth proportional to 79.32, 109.40 and 61.88 is: 85.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.32 : 109.40 = 61.88 : x
  2. Step 2: Convert to fraction form
    79.32/109.40 = 61.88/x
  3. Step 3: Cross multiply
    79.32x = 109.40 × 61.88
  4. Step 4: Simplify right side
    79.32x = 6,768.82
  5. Step 5: Solve for x
    x = 6,768.82/79.32
  6. Step 6: Final answer
    x = 85.34

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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.