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Finding the Fourth Proportional to 1,380.12, 1,904.94 and 813.45

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Solution

The fourth proportional to 1,380.12, 1,904.94 and 813.45 is: 1,122.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,380.12 : 1,904.94 = 813.45 : x
  2. Step 2: Convert to fraction form
    1,380.12/1,904.94 = 813.45/x
  3. Step 3: Cross multiply
    1,380.12x = 1,904.94 × 813.45
  4. Step 4: Simplify right side
    1,380.12x = 1,549,573.44
  5. Step 5: Solve for x
    x = 1,549,573.44/1,380.12
  6. Step 6: Final answer
    x = 1,122.78

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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.