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Finding the Fourth Proportional to 861.21, 1,188.36 and 488.19

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Solution

The fourth proportional to 861.21, 1,188.36 and 488.19 is: 673.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.21 : 1,188.36 = 488.19 : x
  2. Step 2: Convert to fraction form
    861.21/1,188.36 = 488.19/x
  3. Step 3: Cross multiply
    861.21x = 1,188.36 × 488.19
  4. Step 4: Simplify right side
    861.21x = 580,145.47
  5. Step 5: Solve for x
    x = 580,145.47/861.21
  6. Step 6: Final answer
    x = 673.64

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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.