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Finding the Fourth Proportional to 485.75, 670.29 and 289.31

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Solution

The fourth proportional to 485.75, 670.29 and 289.31 is: 399.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.75 : 670.29 = 289.31 : x
  2. Step 2: Convert to fraction form
    485.75/670.29 = 289.31/x
  3. Step 3: Cross multiply
    485.75x = 670.29 × 289.31
  4. Step 4: Simplify right side
    485.75x = 193,921.60
  5. Step 5: Solve for x
    x = 193,921.60/485.75
  6. Step 6: Final answer
    x = 399.22

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.