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Finding the Fourth Proportional to 780.08, 1,169.78 and 259.94

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Solution

The fourth proportional to 780.08, 1,169.78 and 259.94 is: 389.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.08 : 1,169.78 = 259.94 : x
  2. Step 2: Convert to fraction form
    780.08/1,169.78 = 259.94/x
  3. Step 3: Cross multiply
    780.08x = 1,169.78 × 259.94
  4. Step 4: Simplify right side
    780.08x = 304,065.46
  5. Step 5: Solve for x
    x = 304,065.46/780.08
  6. Step 6: Final answer
    x = 389.79

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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.