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Finding the Fourth Proportional to 390.44, 538.47 and 280.64

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Solution

The fourth proportional to 390.44, 538.47 and 280.64 is: 387.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.44 : 538.47 = 280.64 : x
  2. Step 2: Convert to fraction form
    390.44/538.47 = 280.64/x
  3. Step 3: Cross multiply
    390.44x = 538.47 × 280.64
  4. Step 4: Simplify right side
    390.44x = 151,117.57
  5. Step 5: Solve for x
    x = 151,117.57/390.44
  6. Step 6: Final answer
    x = 387.04

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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.