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Finding the Fourth Proportional to 1,581.36, 2,181.36 and 990.87

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Solution

The fourth proportional to 1,581.36, 2,181.36 and 990.87 is: 1,366.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,581.36 : 2,181.36 = 990.87 : x
  2. Step 2: Convert to fraction form
    1,581.36/2,181.36 = 990.87/x
  3. Step 3: Cross multiply
    1,581.36x = 2,181.36 × 990.87
  4. Step 4: Simplify right side
    1,581.36x = 2,161,439.72
  5. Step 5: Solve for x
    x = 2,161,439.72/1,581.36
  6. Step 6: Final answer
    x = 1,366.83

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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.