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Finding the Fourth Proportional to 1,289.12, 1,780.80 and 1,026.80

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Solution

The fourth proportional to 1,289.12, 1,780.80 and 1,026.80 is: 1,418.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,289.12 : 1,780.80 = 1,026.80 : x
  2. Step 2: Convert to fraction form
    1,289.12/1,780.80 = 1,026.80/x
  3. Step 3: Cross multiply
    1,289.12x = 1,780.80 × 1,026.80
  4. Step 4: Simplify right side
    1,289.12x = 1,828,525.44
  5. Step 5: Solve for x
    x = 1,828,525.44/1,289.12
  6. Step 6: Final answer
    x = 1,418.43

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.