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Finding the Fourth Proportional to 485.69, 670.35 and 289.31

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Solution

The fourth proportional to 485.69, 670.35 and 289.31 is: 399.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.69 : 670.35 = 289.31 : x
  2. Step 2: Convert to fraction form
    485.69/670.35 = 289.31/x
  3. Step 3: Cross multiply
    485.69x = 670.35 × 289.31
  4. Step 4: Simplify right side
    485.69x = 193,938.96
  5. Step 5: Solve for x
    x = 193,938.96/485.69
  6. Step 6: Final answer
    x = 399.31

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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.