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Finding the Fourth Proportional to 721.45, 995.61 and 389.88

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Solution

The fourth proportional to 721.45, 995.61 and 389.88 is: 538.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.45 : 995.61 = 389.88 : x
  2. Step 2: Convert to fraction form
    721.45/995.61 = 389.88/x
  3. Step 3: Cross multiply
    721.45x = 995.61 × 389.88
  4. Step 4: Simplify right side
    721.45x = 388,161.50
  5. Step 5: Solve for x
    x = 388,161.50/721.45
  6. Step 6: Final answer
    x = 538.03

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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.