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Finding the Fourth Proportional to 1,331.49, 1,998.63 and 638.75

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Solution

The fourth proportional to 1,331.49, 1,998.63 and 638.75 is: 958.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,331.49 : 1,998.63 = 638.75 : x
  2. Step 2: Convert to fraction form
    1,331.49/1,998.63 = 638.75/x
  3. Step 3: Cross multiply
    1,331.49x = 1,998.63 × 638.75
  4. Step 4: Simplify right side
    1,331.49x = 1,276,614.92
  5. Step 5: Solve for x
    x = 1,276,614.92/1,331.49
  6. Step 6: Final answer
    x = 958.79

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.