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Finding the Fourth Proportional to 431.20, 647.10 and 309.57

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Solution

The fourth proportional to 431.20, 647.10 and 309.57 is: 464.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.20 : 647.10 = 309.57 : x
  2. Step 2: Convert to fraction form
    431.20/647.10 = 309.57/x
  3. Step 3: Cross multiply
    431.20x = 647.10 × 309.57
  4. Step 4: Simplify right side
    431.20x = 200,319.51
  5. Step 5: Solve for x
    x = 200,319.51/431.20
  6. Step 6: Final answer
    x = 464.56

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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.