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Finding the Fourth Proportional to 6,921, 10,382.40 and 1,990.80

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Solution

The fourth proportional to 6,921, 10,382.40 and 1,990.80 is: 2,986.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    6,921 : 10,382.40 = 1,990.80 : x
  2. Step 2: Convert to fraction form
    6,921/10,382.40 = 1,990.80/x
  3. Step 3: Cross multiply
    6,921x = 10,382.40 × 1,990.80
  4. Step 4: Simplify right side
    6,921x = 20,669,281.92
  5. Step 5: Solve for x
    x = 20,669,281.92/6,921
  6. Step 6: Final answer
    x = 2,986.46

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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.