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Finding the Fourth Proportional to 390.80, 538.80 and 274.52

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Solution

The fourth proportional to 390.80, 538.80 and 274.52 is: 378.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.80 : 538.80 = 274.52 : x
  2. Step 2: Convert to fraction form
    390.80/538.80 = 274.52/x
  3. Step 3: Cross multiply
    390.80x = 538.80 × 274.52
  4. Step 4: Simplify right side
    390.80x = 147,911.38
  5. Step 5: Solve for x
    x = 147,911.38/390.80
  6. Step 6: Final answer
    x = 378.48

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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.