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Finding the Fourth Proportional to 213.45, 320.21 and 90.12

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Solution

The fourth proportional to 213.45, 320.21 and 90.12 is: 135.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.45 : 320.21 = 90.12 : x
  2. Step 2: Convert to fraction form
    213.45/320.21 = 90.12/x
  3. Step 3: Cross multiply
    213.45x = 320.21 × 90.12
  4. Step 4: Simplify right side
    213.45x = 28,857.33
  5. Step 5: Solve for x
    x = 28,857.33/213.45
  6. Step 6: Final answer
    x = 135.19

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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.