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Finding the Fourth Proportional to 390.69, 538.97 and 303.21

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Solution

The fourth proportional to 390.69, 538.97 and 303.21 is: 418.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.69 : 538.97 = 303.21 : x
  2. Step 2: Convert to fraction form
    390.69/538.97 = 303.21/x
  3. Step 3: Cross multiply
    390.69x = 538.97 × 303.21
  4. Step 4: Simplify right side
    390.69x = 163,419.58
  5. Step 5: Solve for x
    x = 163,419.58/390.69
  6. Step 6: Final answer
    x = 418.28

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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.