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Finding the Fourth Proportional to 861.30, 1,291.93 and 212.03

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Solution

The fourth proportional to 861.30, 1,291.93 and 212.03 is: 318.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.30 : 1,291.93 = 212.03 : x
  2. Step 2: Convert to fraction form
    861.30/1,291.93 = 212.03/x
  3. Step 3: Cross multiply
    861.30x = 1,291.93 × 212.03
  4. Step 4: Simplify right side
    861.30x = 273,927.92
  5. Step 5: Solve for x
    x = 273,927.92/861.30
  6. Step 6: Final answer
    x = 318.04

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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.