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Finding the Fourth Proportional to 721.63, 995.84 and 390.05

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Solution

The fourth proportional to 721.63, 995.84 and 390.05 is: 538.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.63 : 995.84 = 390.05 : x
  2. Step 2: Convert to fraction form
    721.63/995.84 = 390.05/x
  3. Step 3: Cross multiply
    721.63x = 995.84 × 390.05
  4. Step 4: Simplify right side
    721.63x = 388,429.88
  5. Step 5: Solve for x
    x = 388,429.88/721.63
  6. Step 6: Final answer
    x = 538.27

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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.