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Finding the Fourth Proportional to 980.80, 1,354.19 and 640.69

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Solution

The fourth proportional to 980.80, 1,354.19 and 640.69 is: 884.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    980.80 : 1,354.19 = 640.69 : x
  2. Step 2: Convert to fraction form
    980.80/1,354.19 = 640.69/x
  3. Step 3: Cross multiply
    980.80x = 1,354.19 × 640.69
  4. Step 4: Simplify right side
    980.80x = 867,620.62
  5. Step 5: Solve for x
    x = 867,620.62/980.80
  6. Step 6: Final answer
    x = 884.61

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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.