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Finding the Fourth Proportional to 1,399.32, 1,930.80 and 778.32

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Solution

The fourth proportional to 1,399.32, 1,930.80 and 778.32 is: 1,073.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,399.32 : 1,930.80 = 778.32 : x
  2. Step 2: Convert to fraction form
    1,399.32/1,930.80 = 778.32/x
  3. Step 3: Cross multiply
    1,399.32x = 1,930.80 × 778.32
  4. Step 4: Simplify right side
    1,399.32x = 1,502,780.26
  5. Step 5: Solve for x
    x = 1,502,780.26/1,399.32
  6. Step 6: Final answer
    x = 1,073.94

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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.