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Finding the Fourth Proportional to 1,290.62, 1,936.20 and 641.00

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Solution

The fourth proportional to 1,290.62, 1,936.20 and 641.00 is: 961.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,290.62 : 1,936.20 = 641.00 : x
  2. Step 2: Convert to fraction form
    1,290.62/1,936.20 = 641.00/x
  3. Step 3: Cross multiply
    1,290.62x = 1,936.20 × 641.00
  4. Step 4: Simplify right side
    1,290.62x = 1,241,111.44
  5. Step 5: Solve for x
    x = 1,241,111.44/1,290.62
  6. Step 6: Final answer
    x = 961.64

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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.