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Finding the Fourth Proportional to 485.75, 728.21 and 211.64

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Solution

The fourth proportional to 485.75, 728.21 and 211.64 is: 317.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.75 : 728.21 = 211.64 : x
  2. Step 2: Convert to fraction form
    485.75/728.21 = 211.64/x
  3. Step 3: Cross multiply
    485.75x = 728.21 × 211.64
  4. Step 4: Simplify right side
    485.75x = 154,115.25
  5. Step 5: Solve for x
    x = 154,115.25/485.75
  6. Step 6: Final answer
    x = 317.27

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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.