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Finding the Fourth Proportional to 861.93, 1,290.80 and 818.87

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Solution

The fourth proportional to 861.93, 1,290.80 and 818.87 is: 1,226.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.93 : 1,290.80 = 818.87 : x
  2. Step 2: Convert to fraction form
    861.93/1,290.80 = 818.87/x
  3. Step 3: Cross multiply
    861.93x = 1,290.80 × 818.87
  4. Step 4: Simplify right side
    861.93x = 1,056,986.85
  5. Step 5: Solve for x
    x = 1,056,986.85/861.93
  6. Step 6: Final answer
    x = 1,226.30

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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.