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Finding the Fourth Proportional to 3,121.70, 4,682.64 and 813.20

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Solution

The fourth proportional to 3,121.70, 4,682.64 and 813.20 is: 1,219.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    3,121.70 : 4,682.64 = 813.20 : x
  2. Step 2: Convert to fraction form
    3,121.70/4,682.64 = 813.20/x
  3. Step 3: Cross multiply
    3,121.70x = 4,682.64 × 813.20
  4. Step 4: Simplify right side
    3,121.70x = 3,807,899.43
  5. Step 5: Solve for x
    x = 3,807,899.43/3,121.70
  6. Step 6: Final answer
    x = 1,219.82

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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.