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Finding the Fourth Proportional to 999.12, 1,378.83 and 667.68

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Solution

The fourth proportional to 999.12, 1,378.83 and 667.68 is: 921.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.12 : 1,378.83 = 667.68 : x
  2. Step 2: Convert to fraction form
    999.12/1,378.83 = 667.68/x
  3. Step 3: Cross multiply
    999.12x = 1,378.83 × 667.68
  4. Step 4: Simplify right side
    999.12x = 920,617.21
  5. Step 5: Solve for x
    x = 920,617.21/999.12
  6. Step 6: Final answer
    x = 921.43

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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.