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Finding the Fourth Proportional to 79, 109.08 and 61.72

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Solution

The fourth proportional to 79, 109.08 and 61.72 is: 85.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    79 : 109.08 = 61.72 : x
  2. Step 2: Convert to fraction form
    79/109.08 = 61.72/x
  3. Step 3: Cross multiply
    79x = 109.08 × 61.72
  4. Step 4: Simplify right side
    79x = 6,732.42
  5. Step 5: Solve for x
    x = 6,732.42/79
  6. Step 6: Final answer
    x = 85.22

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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.