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Finding the Fourth Proportional to 780.66, 1,170.20 and 434.15

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Solution

The fourth proportional to 780.66, 1,170.20 and 434.15 is: 650.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.66 : 1,170.20 = 434.15 : x
  2. Step 2: Convert to fraction form
    780.66/1,170.20 = 434.15/x
  3. Step 3: Cross multiply
    780.66x = 1,170.20 × 434.15
  4. Step 4: Simplify right side
    780.66x = 508,034.31
  5. Step 5: Solve for x
    x = 508,034.31/780.66
  6. Step 6: Final answer
    x = 650.78

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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.