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Finding the Fourth Proportional to 79.71, 109.93 and 79.31

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Solution

The fourth proportional to 79.71, 109.93 and 79.31 is: 109.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.71 : 109.93 = 79.31 : x
  2. Step 2: Convert to fraction form
    79.71/109.93 = 79.31/x
  3. Step 3: Cross multiply
    79.71x = 109.93 × 79.31
  4. Step 4: Simplify right side
    79.71x = 8,718.55
  5. Step 5: Solve for x
    x = 8,718.55/79.71
  6. Step 6: Final answer
    x = 109.38

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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.