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Finding the Fourth Proportional to 1,399.88, 1,931.84 and 778.88

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Solution

The fourth proportional to 1,399.88, 1,931.84 and 778.88 is: 1,074.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,399.88 : 1,931.84 = 778.88 : x
  2. Step 2: Convert to fraction form
    1,399.88/1,931.84 = 778.88/x
  3. Step 3: Cross multiply
    1,399.88x = 1,931.84 × 778.88
  4. Step 4: Simplify right side
    1,399.88x = 1,504,671.54
  5. Step 5: Solve for x
    x = 1,504,671.54/1,399.88
  6. Step 6: Final answer
    x = 1,074.86

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.