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Finding the Fourth Proportional to 861.63, 1,291.66 and 313.69

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Solution

The fourth proportional to 861.63, 1,291.66 and 313.69 is: 470.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.63 : 1,291.66 = 313.69 : x
  2. Step 2: Convert to fraction form
    861.63/1,291.66 = 313.69/x
  3. Step 3: Cross multiply
    861.63x = 1,291.66 × 313.69
  4. Step 4: Simplify right side
    861.63x = 405,180.83
  5. Step 5: Solve for x
    x = 405,180.83/861.63
  6. Step 6: Final answer
    x = 470.25

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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.