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Finding the Fourth Proportional to 390.68, 538.58 and 243.21

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Solution

The fourth proportional to 390.68, 538.58 and 243.21 is: 335.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.68 : 538.58 = 243.21 : x
  2. Step 2: Convert to fraction form
    390.68/538.58 = 243.21/x
  3. Step 3: Cross multiply
    390.68x = 538.58 × 243.21
  4. Step 4: Simplify right side
    390.68x = 130,988.65
  5. Step 5: Solve for x
    x = 130,988.65/390.68
  6. Step 6: Final answer
    x = 335.29

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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.