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Finding the Fourth Proportional to 781.68, 1,172.49 and 319.47

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Solution

The fourth proportional to 781.68, 1,172.49 and 319.47 is: 479.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.68 : 1,172.49 = 319.47 : x
  2. Step 2: Convert to fraction form
    781.68/1,172.49 = 319.47/x
  3. Step 3: Cross multiply
    781.68x = 1,172.49 × 319.47
  4. Step 4: Simplify right side
    781.68x = 374,569.79
  5. Step 5: Solve for x
    x = 374,569.79/781.68
  6. Step 6: Final answer
    x = 479.19

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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.