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Finding the Fourth Proportional to 1,280.90, 1,918.94 and 731.43

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Solution

The fourth proportional to 1,280.90, 1,918.94 and 731.43 is: 1,095.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.90 : 1,918.94 = 731.43 : x
  2. Step 2: Convert to fraction form
    1,280.90/1,918.94 = 731.43/x
  3. Step 3: Cross multiply
    1,280.90x = 1,918.94 × 731.43
  4. Step 4: Simplify right side
    1,280.90x = 1,403,566.63
  5. Step 5: Solve for x
    x = 1,403,566.63/1,280.90
  6. Step 6: Final answer
    x = 1,095.76

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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.