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Finding the Fourth Proportional to 857.61, 1,287.09 and 447.09

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Solution

The fourth proportional to 857.61, 1,287.09 and 447.09 is: 670.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.61 : 1,287.09 = 447.09 : x
  2. Step 2: Convert to fraction form
    857.61/1,287.09 = 447.09/x
  3. Step 3: Cross multiply
    857.61x = 1,287.09 × 447.09
  4. Step 4: Simplify right side
    857.61x = 575,445.07
  5. Step 5: Solve for x
    x = 575,445.07/857.61
  6. Step 6: Final answer
    x = 670.99

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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.