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Finding the Fourth Proportional to 79.70, 118.90 and 69.57

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Solution

The fourth proportional to 79.70, 118.90 and 69.57 is: 103.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.70 : 118.90 = 69.57 : x
  2. Step 2: Convert to fraction form
    79.70/118.90 = 69.57/x
  3. Step 3: Cross multiply
    79.70x = 118.90 × 69.57
  4. Step 4: Simplify right side
    79.70x = 8,271.87
  5. Step 5: Solve for x
    x = 8,271.87/79.70
  6. Step 6: Final answer
    x = 103.79

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.