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Finding the Fourth Proportional to 485.65, 670.42 and 286.42

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Solution

The fourth proportional to 485.65, 670.42 and 286.42 is: 395.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.65 : 670.42 = 286.42 : x
  2. Step 2: Convert to fraction form
    485.65/670.42 = 286.42/x
  3. Step 3: Cross multiply
    485.65x = 670.42 × 286.42
  4. Step 4: Simplify right side
    485.65x = 192,018.34
  5. Step 5: Solve for x
    x = 192,018.34/485.65
  6. Step 6: Final answer
    x = 395.39

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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.