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Finding the Fourth Proportional to 781.86, 1,172.88 and 204.78

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Solution

The fourth proportional to 781.86, 1,172.88 and 204.78 is: 307.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.86 : 1,172.88 = 204.78 : x
  2. Step 2: Convert to fraction form
    781.86/1,172.88 = 204.78/x
  3. Step 3: Cross multiply
    781.86x = 1,172.88 × 204.78
  4. Step 4: Simplify right side
    781.86x = 240,182.37
  5. Step 5: Solve for x
    x = 240,182.37/781.86
  6. Step 6: Final answer
    x = 307.19

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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.