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Finding the Fourth Proportional to 2,809.82, 4,215 and 861.68

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Solution

The fourth proportional to 2,809.82, 4,215 and 861.68 is: 1,292.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,809.82 : 4,215 = 861.68 : x
  2. Step 2: Convert to fraction form
    2,809.82/4,215 = 861.68/x
  3. Step 3: Cross multiply
    2,809.82x = 4,215 × 861.68
  4. Step 4: Simplify right side
    2,809.82x = 3,631,981.20
  5. Step 5: Solve for x
    x = 3,631,981.20/2,809.82
  6. Step 6: Final answer
    x = 1,292.60

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.