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Finding the Fourth Proportional to 1,286.20, 1,928.34 and 920.76

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Solution

The fourth proportional to 1,286.20, 1,928.34 and 920.76 is: 1,380.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,286.20 : 1,928.34 = 920.76 : x
  2. Step 2: Convert to fraction form
    1,286.20/1,928.34 = 920.76/x
  3. Step 3: Cross multiply
    1,286.20x = 1,928.34 × 920.76
  4. Step 4: Simplify right side
    1,286.20x = 1,775,538.34
  5. Step 5: Solve for x
    x = 1,775,538.34/1,286.20
  6. Step 6: Final answer
    x = 1,380.45

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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.