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Finding the Fourth Proportional to 778.80, 1,074.78 and 499.28

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Solution

The fourth proportional to 778.80, 1,074.78 and 499.28 is: 689.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    778.80 : 1,074.78 = 499.28 : x
  2. Step 2: Convert to fraction form
    778.80/1,074.78 = 499.28/x
  3. Step 3: Cross multiply
    778.80x = 1,074.78 × 499.28
  4. Step 4: Simplify right side
    778.80x = 536,616.16
  5. Step 5: Solve for x
    x = 536,616.16/778.80
  6. Step 6: Final answer
    x = 689.03

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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.