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Finding the Fourth Proportional to 2,139.09, 3,208.95 and 678.66

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Solution

The fourth proportional to 2,139.09, 3,208.95 and 678.66 is: 1,018.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,139.09 : 3,208.95 = 678.66 : x
  2. Step 2: Convert to fraction form
    2,139.09/3,208.95 = 678.66/x
  3. Step 3: Cross multiply
    2,139.09x = 3,208.95 × 678.66
  4. Step 4: Simplify right side
    2,139.09x = 2,177,786.01
  5. Step 5: Solve for x
    x = 2,177,786.01/2,139.09
  6. Step 6: Final answer
    x = 1,018.09

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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.