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Finding the Fourth Proportional to 778.16, 1,074.66 and 645.86

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Solution

The fourth proportional to 778.16, 1,074.66 and 645.86 is: 891.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    778.16 : 1,074.66 = 645.86 : x
  2. Step 2: Convert to fraction form
    778.16/1,074.66 = 645.86/x
  3. Step 3: Cross multiply
    778.16x = 1,074.66 × 645.86
  4. Step 4: Simplify right side
    778.16x = 694,079.91
  5. Step 5: Solve for x
    x = 694,079.91/778.16
  6. Step 6: Final answer
    x = 891.95

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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.