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Finding the Fourth Proportional to 538.20, 742.50 and 390.51

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Solution

The fourth proportional to 538.20, 742.50 and 390.51 is: 538.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    538.20 : 742.50 = 390.51 : x
  2. Step 2: Convert to fraction form
    538.20/742.50 = 390.51/x
  3. Step 3: Cross multiply
    538.20x = 742.50 × 390.51
  4. Step 4: Simplify right side
    538.20x = 289,953.68
  5. Step 5: Solve for x
    x = 289,953.68/538.20
  6. Step 6: Final answer
    x = 538.75

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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.