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Finding the Fourth Proportional to 505.09, 757.53 and 139.78

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Solution

The fourth proportional to 505.09, 757.53 and 139.78 is: 209.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    505.09 : 757.53 = 139.78 : x
  2. Step 2: Convert to fraction form
    505.09/757.53 = 139.78/x
  3. Step 3: Cross multiply
    505.09x = 757.53 × 139.78
  4. Step 4: Simplify right side
    505.09x = 105,885.65
  5. Step 5: Solve for x
    x = 105,885.65/505.09
  6. Step 6: Final answer
    x = 209.64

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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.