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Finding the Fourth Proportional to 212.65, 319.33 and 138.65

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Solution

The fourth proportional to 212.65, 319.33 and 138.65 is: 208.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.65 : 319.33 = 138.65 : x
  2. Step 2: Convert to fraction form
    212.65/319.33 = 138.65/x
  3. Step 3: Cross multiply
    212.65x = 319.33 × 138.65
  4. Step 4: Simplify right side
    212.65x = 44,275.10
  5. Step 5: Solve for x
    x = 44,275.10/212.65
  6. Step 6: Final answer
    x = 208.21

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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.