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Finding the Fourth Proportional to 987.09, 1,478.21 and 794.31

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Solution

The fourth proportional to 987.09, 1,478.21 and 794.31 is: 1,189.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.09 : 1,478.21 = 794.31 : x
  2. Step 2: Convert to fraction form
    987.09/1,478.21 = 794.31/x
  3. Step 3: Cross multiply
    987.09x = 1,478.21 × 794.31
  4. Step 4: Simplify right side
    987.09x = 1,174,153.01
  5. Step 5: Solve for x
    x = 1,174,153.01/987.09
  6. Step 6: Final answer
    x = 1,189.51

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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.