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Finding the Fourth Proportional to 812.15, 1,120.78 and 462.86

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Solution

The fourth proportional to 812.15, 1,120.78 and 462.86 is: 638.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.15 : 1,120.78 = 462.86 : x
  2. Step 2: Convert to fraction form
    812.15/1,120.78 = 462.86/x
  3. Step 3: Cross multiply
    812.15x = 1,120.78 × 462.86
  4. Step 4: Simplify right side
    812.15x = 518,761.92
  5. Step 5: Solve for x
    x = 518,761.92/812.15
  6. Step 6: Final answer
    x = 638.75

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1.5x scale

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.