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Finding the Fourth Proportional to 505.78, 758.43 and 213.21

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Solution

The fourth proportional to 505.78, 758.43 and 213.21 is: 319.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    505.78 : 758.43 = 213.21 : x
  2. Step 2: Convert to fraction form
    505.78/758.43 = 213.21/x
  3. Step 3: Cross multiply
    505.78x = 758.43 × 213.21
  4. Step 4: Simplify right side
    505.78x = 161,704.86
  5. Step 5: Solve for x
    x = 161,704.86/505.78
  6. Step 6: Final answer
    x = 319.72

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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.