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Finding the Fourth Proportional to 861.02, 1,291.12 and 312.82

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Solution

The fourth proportional to 861.02, 1,291.12 and 312.82 is: 469.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.02 : 1,291.12 = 312.82 : x
  2. Step 2: Convert to fraction form
    861.02/1,291.12 = 312.82/x
  3. Step 3: Cross multiply
    861.02x = 1,291.12 × 312.82
  4. Step 4: Simplify right side
    861.02x = 403,884.15
  5. Step 5: Solve for x
    x = 403,884.15/861.02
  6. Step 6: Final answer
    x = 469.08

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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.