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Finding the Fourth Proportional to 1,292.80, 1,939.22 and 830.78

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Solution

The fourth proportional to 1,292.80, 1,939.22 and 830.78 is: 1,246.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,292.80 : 1,939.22 = 830.78 : x
  2. Step 2: Convert to fraction form
    1,292.80/1,939.22 = 830.78/x
  3. Step 3: Cross multiply
    1,292.80x = 1,939.22 × 830.78
  4. Step 4: Simplify right side
    1,292.80x = 1,611,065.19
  5. Step 5: Solve for x
    x = 1,611,065.19/1,292.80
  6. Step 6: Final answer
    x = 1,246.18

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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.