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Finding the Fourth Proportional to 431.98, 647.86 and 215.50

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Solution

The fourth proportional to 431.98, 647.86 and 215.50 is: 323.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.98 : 647.86 = 215.50 : x
  2. Step 2: Convert to fraction form
    431.98/647.86 = 215.50/x
  3. Step 3: Cross multiply
    431.98x = 647.86 × 215.50
  4. Step 4: Simplify right side
    431.98x = 139,613.83
  5. Step 5: Solve for x
    x = 139,613.83/431.98
  6. Step 6: Final answer
    x = 323.20

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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.