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Finding the Fourth Proportional to 991.92, 1,490.79 and 479.28

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Solution

The fourth proportional to 991.92, 1,490.79 and 479.28 is: 720.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.92 : 1,490.79 = 479.28 : x
  2. Step 2: Convert to fraction form
    991.92/1,490.79 = 479.28/x
  3. Step 3: Cross multiply
    991.92x = 1,490.79 × 479.28
  4. Step 4: Simplify right side
    991.92x = 714,505.83
  5. Step 5: Solve for x
    x = 714,505.83/991.92
  6. Step 6: Final answer
    x = 720.33

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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.