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Finding the Fourth Proportional to 213.21, 319.86 and 105.12

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Solution

The fourth proportional to 213.21, 319.86 and 105.12 is: 157.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.21 : 319.86 = 105.12 : x
  2. Step 2: Convert to fraction form
    213.21/319.86 = 105.12/x
  3. Step 3: Cross multiply
    213.21x = 319.86 × 105.12
  4. Step 4: Simplify right side
    213.21x = 33,623.68
  5. Step 5: Solve for x
    x = 33,623.68/213.21
  6. Step 6: Final answer
    x = 157.70

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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.