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Finding the Fourth Proportional to 861.57, 1,291.82 and 305.91

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Solution

The fourth proportional to 861.57, 1,291.82 and 305.91 is: 458.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.57 : 1,291.82 = 305.91 : x
  2. Step 2: Convert to fraction form
    861.57/1,291.82 = 305.91/x
  3. Step 3: Cross multiply
    861.57x = 1,291.82 × 305.91
  4. Step 4: Simplify right side
    861.57x = 395,179.13
  5. Step 5: Solve for x
    x = 395,179.13/861.57
  6. Step 6: Final answer
    x = 458.67

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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.