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Finding the Fourth Proportional to 213.69, 320.57 and 76.70

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Solution

The fourth proportional to 213.69, 320.57 and 76.70 is: 115.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.69 : 320.57 = 76.70 : x
  2. Step 2: Convert to fraction form
    213.69/320.57 = 76.70/x
  3. Step 3: Cross multiply
    213.69x = 320.57 × 76.70
  4. Step 4: Simplify right side
    213.69x = 24,587.72
  5. Step 5: Solve for x
    x = 24,587.72/213.69
  6. Step 6: Final answer
    x = 115.06

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.