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Finding the Fourth Proportional to 1,285.90, 1,928.85 and 669.28

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Solution

The fourth proportional to 1,285.90, 1,928.85 and 669.28 is: 1,003.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,285.90 : 1,928.85 = 669.28 : x
  2. Step 2: Convert to fraction form
    1,285.90/1,928.85 = 669.28/x
  3. Step 3: Cross multiply
    1,285.90x = 1,928.85 × 669.28
  4. Step 4: Simplify right side
    1,285.90x = 1,290,940.73
  5. Step 5: Solve for x
    x = 1,290,940.73/1,285.90
  6. Step 6: Final answer
    x = 1,003.92

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Similar ratio
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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.