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Finding the Fourth Proportional to 213.65, 320.83 and 139.65

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Solution

The fourth proportional to 213.65, 320.83 and 139.65 is: 209.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.65 : 320.83 = 139.65 : x
  2. Step 2: Convert to fraction form
    213.65/320.83 = 139.65/x
  3. Step 3: Cross multiply
    213.65x = 320.83 × 139.65
  4. Step 4: Simplify right side
    213.65x = 44,803.91
  5. Step 5: Solve for x
    x = 44,803.91/213.65
  6. Step 6: Final answer
    x = 209.71

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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.