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Finding the Fourth Proportional to 991.70, 1,477.05 and 939.65

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Solution

The fourth proportional to 991.70, 1,477.05 and 939.65 is: 1,399.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.70 : 1,477.05 = 939.65 : x
  2. Step 2: Convert to fraction form
    991.70/1,477.05 = 939.65/x
  3. Step 3: Cross multiply
    991.70x = 1,477.05 × 939.65
  4. Step 4: Simplify right side
    991.70x = 1,387,902.65
  5. Step 5: Solve for x
    x = 1,387,902.65/991.70
  6. Step 6: Final answer
    x = 1,399.53

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.