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Finding the Fourth Proportional to 288.96, 398.40 and 211.20

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Solution

The fourth proportional to 288.96, 398.40 and 211.20 is: 291.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    288.96 : 398.40 = 211.20 : x
  2. Step 2: Convert to fraction form
    288.96/398.40 = 211.20/x
  3. Step 3: Cross multiply
    288.96x = 398.40 × 211.20
  4. Step 4: Simplify right side
    288.96x = 84,142.08
  5. Step 5: Solve for x
    x = 84,142.08/288.96
  6. Step 6: Final answer
    x = 291.19

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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.