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Finding the Fourth Proportional to 660.64, 911.64 and 398.80

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Solution

The fourth proportional to 660.64, 911.64 and 398.80 is: 550.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.64 : 911.64 = 398.80 : x
  2. Step 2: Convert to fraction form
    660.64/911.64 = 398.80/x
  3. Step 3: Cross multiply
    660.64x = 911.64 × 398.80
  4. Step 4: Simplify right side
    660.64x = 363,562.03
  5. Step 5: Solve for x
    x = 363,562.03/660.64
  6. Step 6: Final answer
    x = 550.32

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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.