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Finding the Fourth Proportional to 1,292.93, 1,939.09 and 643.51

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Solution

The fourth proportional to 1,292.93, 1,939.09 and 643.51 is: 965.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,292.93 : 1,939.09 = 643.51 : x
  2. Step 2: Convert to fraction form
    1,292.93/1,939.09 = 643.51/x
  3. Step 3: Cross multiply
    1,292.93x = 1,939.09 × 643.51
  4. Step 4: Simplify right side
    1,292.93x = 1,247,825.83
  5. Step 5: Solve for x
    x = 1,247,825.83/1,292.93
  6. Step 6: Final answer
    x = 965.12

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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.