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Finding the Fourth Proportional to 861.41, 1,290.35 and 642.26

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Solution

The fourth proportional to 861.41, 1,290.35 and 642.26 is: 962.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.41 : 1,290.35 = 642.26 : x
  2. Step 2: Convert to fraction form
    861.41/1,290.35 = 642.26/x
  3. Step 3: Cross multiply
    861.41x = 1,290.35 × 642.26
  4. Step 4: Simplify right side
    861.41x = 828,745.02
  5. Step 5: Solve for x
    x = 828,745.02/861.41
  6. Step 6: Final answer
    x = 962.08

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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.