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Finding the Fourth Proportional to 258.48, 386.21 and 212.31

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Solution

The fourth proportional to 258.48, 386.21 and 212.31 is: 317.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.48 : 386.21 = 212.31 : x
  2. Step 2: Convert to fraction form
    258.48/386.21 = 212.31/x
  3. Step 3: Cross multiply
    258.48x = 386.21 × 212.31
  4. Step 4: Simplify right side
    258.48x = 81,996.78
  5. Step 5: Solve for x
    x = 81,996.78/258.48
  6. Step 6: Final answer
    x = 317.23

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.