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Finding the Fourth Proportional to 861.36, 1,186.48 and 728.40

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Solution

The fourth proportional to 861.36, 1,186.48 and 728.40 is: 1,003.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.36 : 1,186.48 = 728.40 : x
  2. Step 2: Convert to fraction form
    861.36/1,186.48 = 728.40/x
  3. Step 3: Cross multiply
    861.36x = 1,186.48 × 728.40
  4. Step 4: Simplify right side
    861.36x = 864,232.03
  5. Step 5: Solve for x
    x = 864,232.03/861.36
  6. Step 6: Final answer
    x = 1,003.33

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.