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Finding the Fourth Proportional to 1,680.85, 2,520.99 and 640.81

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Solution

The fourth proportional to 1,680.85, 2,520.99 and 640.81 is: 961.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,680.85 : 2,520.99 = 640.81 : x
  2. Step 2: Convert to fraction form
    1,680.85/2,520.99 = 640.81/x
  3. Step 3: Cross multiply
    1,680.85x = 2,520.99 × 640.81
  4. Step 4: Simplify right side
    1,680.85x = 1,615,475.60
  5. Step 5: Solve for x
    x = 1,615,475.60/1,680.85
  6. Step 6: Final answer
    x = 961.11

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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.