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Finding the Fourth Proportional to 862.15, 1,293.20 and 212.88

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Solution

The fourth proportional to 862.15, 1,293.20 and 212.88 is: 319.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    862.15 : 1,293.20 = 212.88 : x
  2. Step 2: Convert to fraction form
    862.15/1,293.20 = 212.88/x
  3. Step 3: Cross multiply
    862.15x = 1,293.20 × 212.88
  4. Step 4: Simplify right side
    862.15x = 275,296.42
  5. Step 5: Solve for x
    x = 275,296.42/862.15
  6. Step 6: Final answer
    x = 319.31

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.