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Finding the Fourth Proportional to 505.20, 757.80 and 261.80

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Solution

The fourth proportional to 505.20, 757.80 and 261.80 is: 392.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    505.20 : 757.80 = 261.80 : x
  2. Step 2: Convert to fraction form
    505.20/757.80 = 261.80/x
  3. Step 3: Cross multiply
    505.20x = 757.80 × 261.80
  4. Step 4: Simplify right side
    505.20x = 198,392.04
  5. Step 5: Solve for x
    x = 198,392.04/505.20
  6. Step 6: Final answer
    x = 392.70

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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.