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Finding the Fourth Proportional to 408.72, 612.64 and 213.51

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Solution

The fourth proportional to 408.72, 612.64 and 213.51 is: 320.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    408.72 : 612.64 = 213.51 : x
  2. Step 2: Convert to fraction form
    408.72/612.64 = 213.51/x
  3. Step 3: Cross multiply
    408.72x = 612.64 × 213.51
  4. Step 4: Simplify right side
    408.72x = 130,804.77
  5. Step 5: Solve for x
    x = 130,804.77/408.72
  6. Step 6: Final answer
    x = 320.04

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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.