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Finding the Fourth Proportional to 999.12, 1,378.92 and 689.04

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Solution

The fourth proportional to 999.12, 1,378.92 and 689.04 is: 950.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.12 : 1,378.92 = 689.04 : x
  2. Step 2: Convert to fraction form
    999.12/1,378.92 = 689.04/x
  3. Step 3: Cross multiply
    999.12x = 1,378.92 × 689.04
  4. Step 4: Simplify right side
    999.12x = 950,131.04
  5. Step 5: Solve for x
    x = 950,131.04/999.12
  6. Step 6: Final answer
    x = 950.97

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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.