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Finding the Fourth Proportional to 1,239.13, 1,862.54 and 779.86

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Solution

The fourth proportional to 1,239.13, 1,862.54 and 779.86 is: 1,172.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,239.13 : 1,862.54 = 779.86 : x
  2. Step 2: Convert to fraction form
    1,239.13/1,862.54 = 779.86/x
  3. Step 3: Cross multiply
    1,239.13x = 1,862.54 × 779.86
  4. Step 4: Simplify right side
    1,239.13x = 1,452,517.74
  5. Step 5: Solve for x
    x = 1,452,517.74/1,239.13
  6. Step 6: Final answer
    x = 1,172.21

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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.