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Finding the Fourth Proportional to 390.24, 538.52 and 215.57

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Solution

The fourth proportional to 390.24, 538.52 and 215.57 is: 297.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.24 : 538.52 = 215.57 : x
  2. Step 2: Convert to fraction form
    390.24/538.52 = 215.57/x
  3. Step 3: Cross multiply
    390.24x = 538.52 × 215.57
  4. Step 4: Simplify right side
    390.24x = 116,089.02
  5. Step 5: Solve for x
    x = 116,089.02/390.24
  6. Step 6: Final answer
    x = 297.48

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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.