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Finding the Fourth Proportional to 781.64, 1,172.45 and 742.71

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Solution

The fourth proportional to 781.64, 1,172.45 and 742.71 is: 1,114.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.64 : 1,172.45 = 742.71 : x
  2. Step 2: Convert to fraction form
    781.64/1,172.45 = 742.71/x
  3. Step 3: Cross multiply
    781.64x = 1,172.45 × 742.71
  4. Step 4: Simplify right side
    781.64x = 870,792.20
  5. Step 5: Solve for x
    x = 870,792.20/781.64
  6. Step 6: Final answer
    x = 1,114.07

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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.