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Finding the Fourth Proportional to 1,428.96, 1,971.60 and 905.60

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Solution

The fourth proportional to 1,428.96, 1,971.60 and 905.60 is: 1,249.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,428.96 : 1,971.60 = 905.60 : x
  2. Step 2: Convert to fraction form
    1,428.96/1,971.60 = 905.60/x
  3. Step 3: Cross multiply
    1,428.96x = 1,971.60 × 905.60
  4. Step 4: Simplify right side
    1,428.96x = 1,785,480.96
  5. Step 5: Solve for x
    x = 1,785,480.96/1,428.96
  6. Step 6: Final answer
    x = 1,249.50

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.