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Finding the Fourth Proportional to 79.42, 109.66 and 64.90

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Solution

The fourth proportional to 79.42, 109.66 and 64.90 is: 89.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.42 : 109.66 = 64.90 : x
  2. Step 2: Convert to fraction form
    79.42/109.66 = 64.90/x
  3. Step 3: Cross multiply
    79.42x = 109.66 × 64.90
  4. Step 4: Simplify right side
    79.42x = 7,116.93
  5. Step 5: Solve for x
    x = 7,116.93/79.42
  6. Step 6: Final answer
    x = 89.61

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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.