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Finding the Fourth Proportional to 213.64, 320.60 and 91.90

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Solution

The fourth proportional to 213.64, 320.60 and 91.90 is: 137.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.64 : 320.60 = 91.90 : x
  2. Step 2: Convert to fraction form
    213.64/320.60 = 91.90/x
  3. Step 3: Cross multiply
    213.64x = 320.60 × 91.90
  4. Step 4: Simplify right side
    213.64x = 29,463.14
  5. Step 5: Solve for x
    x = 29,463.14/213.64
  6. Step 6: Final answer
    x = 137.91

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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.