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Finding the Fourth Proportional to 990.09, 1,485.81 and 412.97

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Solution

The fourth proportional to 990.09, 1,485.81 and 412.97 is: 619.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.09 : 1,485.81 = 412.97 : x
  2. Step 2: Convert to fraction form
    990.09/1,485.81 = 412.97/x
  3. Step 3: Cross multiply
    990.09x = 1,485.81 × 412.97
  4. Step 4: Simplify right side
    990.09x = 613,587.53
  5. Step 5: Solve for x
    x = 613,587.53/990.09
  6. Step 6: Final answer
    x = 619.73

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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.