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Finding the Fourth Proportional to 79.70, 109.86 and 65.12

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Solution

The fourth proportional to 79.70, 109.86 and 65.12 is: 89.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.70 : 109.86 = 65.12 : x
  2. Step 2: Convert to fraction form
    79.70/109.86 = 65.12/x
  3. Step 3: Cross multiply
    79.70x = 109.86 × 65.12
  4. Step 4: Simplify right side
    79.70x = 7,154.08
  5. Step 5: Solve for x
    x = 7,154.08/79.70
  6. Step 6: Final answer
    x = 89.76

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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.