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Finding the Fourth Proportional to 759.78, 1,139.70 and 272.70

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Solution

The fourth proportional to 759.78, 1,139.70 and 272.70 is: 409.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    759.78 : 1,139.70 = 272.70 : x
  2. Step 2: Convert to fraction form
    759.78/1,139.70 = 272.70/x
  3. Step 3: Cross multiply
    759.78x = 1,139.70 × 272.70
  4. Step 4: Simplify right side
    759.78x = 310,796.19
  5. Step 5: Solve for x
    x = 310,796.19/759.78
  6. Step 6: Final answer
    x = 409.06

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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.