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Finding the Fourth Proportional to 213.08, 319.88 and 139.72

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Solution

The fourth proportional to 213.08, 319.88 and 139.72 is: 209.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.08 : 319.88 = 139.72 : x
  2. Step 2: Convert to fraction form
    213.08/319.88 = 139.72/x
  3. Step 3: Cross multiply
    213.08x = 319.88 × 139.72
  4. Step 4: Simplify right side
    213.08x = 44,693.63
  5. Step 5: Solve for x
    x = 44,693.63/213.08
  6. Step 6: Final answer
    x = 209.75

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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.