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Finding the Fourth Proportional to 1,126.90, 1,689.54 and 640.29

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Solution

The fourth proportional to 1,126.90, 1,689.54 and 640.29 is: 959.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,126.90 : 1,689.54 = 640.29 : x
  2. Step 2: Convert to fraction form
    1,126.90/1,689.54 = 640.29/x
  3. Step 3: Cross multiply
    1,126.90x = 1,689.54 × 640.29
  4. Step 4: Simplify right side
    1,126.90x = 1,081,795.57
  5. Step 5: Solve for x
    x = 1,081,795.57/1,126.90
  6. Step 6: Final answer
    x = 959.97

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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.