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Finding the Fourth Proportional to 861.30, 1,290.96 and 655.20

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Solution

The fourth proportional to 861.30, 1,290.96 and 655.20 is: 982.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.30 : 1,290.96 = 655.20 : x
  2. Step 2: Convert to fraction form
    861.30/1,290.96 = 655.20/x
  3. Step 3: Cross multiply
    861.30x = 1,290.96 × 655.20
  4. Step 4: Simplify right side
    861.30x = 845,836.99
  5. Step 5: Solve for x
    x = 845,836.99/861.30
  6. Step 6: Final answer
    x = 982.05

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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.