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Finding the Fourth Proportional to 485.39, 669.92 and 286.21

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Solution

The fourth proportional to 485.39, 669.92 and 286.21 is: 395.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.39 : 669.92 = 286.21 : x
  2. Step 2: Convert to fraction form
    485.39/669.92 = 286.21/x
  3. Step 3: Cross multiply
    485.39x = 669.92 × 286.21
  4. Step 4: Simplify right side
    485.39x = 191,735.05
  5. Step 5: Solve for x
    x = 191,735.05/485.39
  6. Step 6: Final answer
    x = 395.01

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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.