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Finding the Fourth Proportional to 1,286.30, 1,929.45 and 638.30

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Solution

The fourth proportional to 1,286.30, 1,929.45 and 638.30 is: 957.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,286.30 : 1,929.45 = 638.30 : x
  2. Step 2: Convert to fraction form
    1,286.30/1,929.45 = 638.30/x
  3. Step 3: Cross multiply
    1,286.30x = 1,929.45 × 638.30
  4. Step 4: Simplify right side
    1,286.30x = 1,231,567.94
  5. Step 5: Solve for x
    x = 1,231,567.94/1,286.30
  6. Step 6: Final answer
    x = 957.45

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Double scale
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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.