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Finding the Fourth Proportional to 780.91, 1,170.85 and 260.74

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Solution

The fourth proportional to 780.91, 1,170.85 and 260.74 is: 390.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.91 : 1,170.85 = 260.74 : x
  2. Step 2: Convert to fraction form
    780.91/1,170.85 = 260.74/x
  3. Step 3: Cross multiply
    780.91x = 1,170.85 × 260.74
  4. Step 4: Simplify right side
    780.91x = 305,287.43
  5. Step 5: Solve for x
    x = 305,287.43/780.91
  6. Step 6: Final answer
    x = 390.94

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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.