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Finding the Fourth Proportional to 390.45, 538.79 and 224.64

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Solution

The fourth proportional to 390.45, 538.79 and 224.64 is: 309.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.45 : 538.79 = 224.64 : x
  2. Step 2: Convert to fraction form
    390.45/538.79 = 224.64/x
  3. Step 3: Cross multiply
    390.45x = 538.79 × 224.64
  4. Step 4: Simplify right side
    390.45x = 121,032.66
  5. Step 5: Solve for x
    x = 121,032.66/390.45
  6. Step 6: Final answer
    x = 309.98

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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.