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Finding the Fourth Proportional to 2,639, 3,959.20 and 790.12

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Solution

The fourth proportional to 2,639, 3,959.20 and 790.12 is: 1,185.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,639 : 3,959.20 = 790.12 : x
  2. Step 2: Convert to fraction form
    2,639/3,959.20 = 790.12/x
  3. Step 3: Cross multiply
    2,639x = 3,959.20 × 790.12
  4. Step 4: Simplify right side
    2,639x = 3,128,243.10
  5. Step 5: Solve for x
    x = 3,128,243.10/2,639
  6. Step 6: Final answer
    x = 1,185.39

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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.