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Finding the Fourth Proportional to 485.89, 670.44 and 286.78

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Solution

The fourth proportional to 485.89, 670.44 and 286.78 is: 395.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.89 : 670.44 = 286.78 : x
  2. Step 2: Convert to fraction form
    485.89/670.44 = 286.78/x
  3. Step 3: Cross multiply
    485.89x = 670.44 × 286.78
  4. Step 4: Simplify right side
    485.89x = 192,268.78
  5. Step 5: Solve for x
    x = 192,268.78/485.89
  6. Step 6: Final answer
    x = 395.70

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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.