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Finding the Fourth Proportional to 485.09, 669.45 and 319.40

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Solution

The fourth proportional to 485.09, 669.45 and 319.40 is: 440.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.09 : 669.45 = 319.40 : x
  2. Step 2: Convert to fraction form
    485.09/669.45 = 319.40/x
  3. Step 3: Cross multiply
    485.09x = 669.45 × 319.40
  4. Step 4: Simplify right side
    485.09x = 213,818.98
  5. Step 5: Solve for x
    x = 213,818.98/485.09
  6. Step 6: Final answer
    x = 440.79

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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.