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Finding the Fourth Proportional to 780.57, 1,170.74 and 260.56

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Solution

The fourth proportional to 780.57, 1,170.74 and 260.56 is: 390.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.57 : 1,170.74 = 260.56 : x
  2. Step 2: Convert to fraction form
    780.57/1,170.74 = 260.56/x
  3. Step 3: Cross multiply
    780.57x = 1,170.74 × 260.56
  4. Step 4: Simplify right side
    780.57x = 305,044.73
  5. Step 5: Solve for x
    x = 305,044.73/780.57
  6. Step 6: Final answer
    x = 390.80

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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.