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Finding the Fourth Proportional to 389.99, 538.16 and 215.34

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Solution

The fourth proportional to 389.99, 538.16 and 215.34 is: 297.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.99 : 538.16 = 215.34 : x
  2. Step 2: Convert to fraction form
    389.99/538.16 = 215.34/x
  3. Step 3: Cross multiply
    389.99x = 538.16 × 215.34
  4. Step 4: Simplify right side
    389.99x = 115,887.37
  5. Step 5: Solve for x
    x = 115,887.37/389.99
  6. Step 6: Final answer
    x = 297.15

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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.