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Finding the Fourth Proportional to 420.83, 630.86 and 215.65

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Solution

The fourth proportional to 420.83, 630.86 and 215.65 is: 323.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.83 : 630.86 = 215.65 : x
  2. Step 2: Convert to fraction form
    420.83/630.86 = 215.65/x
  3. Step 3: Cross multiply
    420.83x = 630.86 × 215.65
  4. Step 4: Simplify right side
    420.83x = 136,044.96
  5. Step 5: Solve for x
    x = 136,044.96/420.83
  6. Step 6: Final answer
    x = 323.28

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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.