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Finding the Fourth Proportional to 1,208.12, 1,811.12 and 428.00

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Solution

The fourth proportional to 1,208.12, 1,811.12 and 428.00 is: 641.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,208.12 : 1,811.12 = 428.00 : x
  2. Step 2: Convert to fraction form
    1,208.12/1,811.12 = 428.00/x
  3. Step 3: Cross multiply
    1,208.12x = 1,811.12 × 428.00
  4. Step 4: Simplify right side
    1,208.12x = 775,148.16
  5. Step 5: Solve for x
    x = 775,148.16/1,208.12
  6. Step 6: Final answer
    x = 641.62

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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.