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Finding the Fourth Proportional to 780.86, 1,171.38 and 203.78

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Solution

The fourth proportional to 780.86, 1,171.38 and 203.78 is: 305.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.86 : 1,171.38 = 203.78 : x
  2. Step 2: Convert to fraction form
    780.86/1,171.38 = 203.78/x
  3. Step 3: Cross multiply
    780.86x = 1,171.38 × 203.78
  4. Step 4: Simplify right side
    780.86x = 238,703.82
  5. Step 5: Solve for x
    x = 238,703.82/780.86
  6. Step 6: Final answer
    x = 305.69

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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.