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Finding the Fourth Proportional to 839.72, 1,259.64 and 319.97

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Solution

The fourth proportional to 839.72, 1,259.64 and 319.97 is: 479.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.72 : 1,259.64 = 319.97 : x
  2. Step 2: Convert to fraction form
    839.72/1,259.64 = 319.97/x
  3. Step 3: Cross multiply
    839.72x = 1,259.64 × 319.97
  4. Step 4: Simplify right side
    839.72x = 403,047.01
  5. Step 5: Solve for x
    x = 403,047.01/839.72
  6. Step 6: Final answer
    x = 479.98

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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.