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Finding the Fourth Proportional to 485.56, 728.46 and 431.80

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Solution

The fourth proportional to 485.56, 728.46 and 431.80 is: 647.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.56 : 728.46 = 431.80 : x
  2. Step 2: Convert to fraction form
    485.56/728.46 = 431.80/x
  3. Step 3: Cross multiply
    485.56x = 728.46 × 431.80
  4. Step 4: Simplify right side
    485.56x = 314,549.03
  5. Step 5: Solve for x
    x = 314,549.03/485.56
  6. Step 6: Final answer
    x = 647.81

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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.