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Finding the Fourth Proportional to 1,918.92, 2,878.40 and 620.40

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Solution

The fourth proportional to 1,918.92, 2,878.40 and 620.40 is: 930.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,918.92 : 2,878.40 = 620.40 : x
  2. Step 2: Convert to fraction form
    1,918.92/2,878.40 = 620.40/x
  3. Step 3: Cross multiply
    1,918.92x = 2,878.40 × 620.40
  4. Step 4: Simplify right side
    1,918.92x = 1,785,759.36
  5. Step 5: Solve for x
    x = 1,785,759.36/1,918.92
  6. Step 6: Final answer
    x = 930.61

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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.