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Finding the Fourth Proportional to 781.49, 1,172.27 and 319.74

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Solution

The fourth proportional to 781.49, 1,172.27 and 319.74 is: 479.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.49 : 1,172.27 = 319.74 : x
  2. Step 2: Convert to fraction form
    781.49/1,172.27 = 319.74/x
  3. Step 3: Cross multiply
    781.49x = 1,172.27 × 319.74
  4. Step 4: Simplify right side
    781.49x = 374,820.01
  5. Step 5: Solve for x
    x = 374,820.01/781.49
  6. Step 6: Final answer
    x = 479.62

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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.