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Finding the Fourth Proportional to 778.11, 1,074.45 and 645.22

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Solution

The fourth proportional to 778.11, 1,074.45 and 645.22 is: 890.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    778.11 : 1,074.45 = 645.22 : x
  2. Step 2: Convert to fraction form
    778.11/1,074.45 = 645.22/x
  3. Step 3: Cross multiply
    778.11x = 1,074.45 × 645.22
  4. Step 4: Simplify right side
    778.11x = 693,256.63
  5. Step 5: Solve for x
    x = 693,256.63/778.11
  6. Step 6: Final answer
    x = 890.95

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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.