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Finding the Fourth Proportional to 776.78, 1,072.14 and 445.20

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Solution

The fourth proportional to 776.78, 1,072.14 and 445.20 is: 614.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    776.78 : 1,072.14 = 445.20 : x
  2. Step 2: Convert to fraction form
    776.78/1,072.14 = 445.20/x
  3. Step 3: Cross multiply
    776.78x = 1,072.14 × 445.20
  4. Step 4: Simplify right side
    776.78x = 477,320.64
  5. Step 5: Solve for x
    x = 477,320.64/776.78
  6. Step 6: Final answer
    x = 614.48

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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.