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Finding the Fourth Proportional to 1,020.80, 1,408.76 and 578.78

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Solution

The fourth proportional to 1,020.80, 1,408.76 and 578.78 is: 798.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,020.80 : 1,408.76 = 578.78 : x
  2. Step 2: Convert to fraction form
    1,020.80/1,408.76 = 578.78/x
  3. Step 3: Cross multiply
    1,020.80x = 1,408.76 × 578.78
  4. Step 4: Simplify right side
    1,020.80x = 815,359.63
  5. Step 5: Solve for x
    x = 815,359.63/1,020.80
  6. Step 6: Final answer
    x = 798.74

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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.