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Finding the Fourth Proportional to 431.69, 647.55 and 215.19

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Solution

The fourth proportional to 431.69, 647.55 and 215.19 is: 322.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.69 : 647.55 = 215.19 : x
  2. Step 2: Convert to fraction form
    431.69/647.55 = 215.19/x
  3. Step 3: Cross multiply
    431.69x = 647.55 × 215.19
  4. Step 4: Simplify right side
    431.69x = 139,346.28
  5. Step 5: Solve for x
    x = 139,346.28/431.69
  6. Step 6: Final answer
    x = 322.80

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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.