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Finding the Fourth Proportional to 780.40, 1,169.78 and 260.27

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Solution

The fourth proportional to 780.40, 1,169.78 and 260.27 is: 390.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.40 : 1,169.78 = 260.27 : x
  2. Step 2: Convert to fraction form
    780.40/1,169.78 = 260.27/x
  3. Step 3: Cross multiply
    780.40x = 1,169.78 × 260.27
  4. Step 4: Simplify right side
    780.40x = 304,458.64
  5. Step 5: Solve for x
    x = 304,458.64/780.40
  6. Step 6: Final answer
    x = 390.13

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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.