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Finding the Fourth Proportional to 1,288.45, 1,930.05 and 870.70

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Solution

The fourth proportional to 1,288.45, 1,930.05 and 870.70 is: 1,304.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,288.45 : 1,930.05 = 870.70 : x
  2. Step 2: Convert to fraction form
    1,288.45/1,930.05 = 870.70/x
  3. Step 3: Cross multiply
    1,288.45x = 1,930.05 × 870.70
  4. Step 4: Simplify right side
    1,288.45x = 1,680,494.54
  5. Step 5: Solve for x
    x = 1,680,494.54/1,288.45
  6. Step 6: Final answer
    x = 1,304.28

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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.