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Finding the Fourth Proportional to 390.78, 538.74 and 324.14

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Solution

The fourth proportional to 390.78, 538.74 and 324.14 is: 446.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.78 : 538.74 = 324.14 : x
  2. Step 2: Convert to fraction form
    390.78/538.74 = 324.14/x
  3. Step 3: Cross multiply
    390.78x = 538.74 × 324.14
  4. Step 4: Simplify right side
    390.78x = 174,627.18
  5. Step 5: Solve for x
    x = 174,627.18/390.78
  6. Step 6: Final answer
    x = 446.87

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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.