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Finding the Fourth Proportional to 778.78, 1,075.90 and 661.99

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Solution

The fourth proportional to 778.78, 1,075.90 and 661.99 is: 914.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    778.78 : 1,075.90 = 661.99 : x
  2. Step 2: Convert to fraction form
    778.78/1,075.90 = 661.99/x
  3. Step 3: Cross multiply
    778.78x = 1,075.90 × 661.99
  4. Step 4: Simplify right side
    778.78x = 712,241.02
  5. Step 5: Solve for x
    x = 712,241.02/778.78
  6. Step 6: Final answer
    x = 914.56

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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.