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Finding the Fourth Proportional to 288.80, 431.36 and 261.92

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Solution

The fourth proportional to 288.80, 431.36 and 261.92 is: 391.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    288.80 : 431.36 = 261.92 : x
  2. Step 2: Convert to fraction form
    288.80/431.36 = 261.92/x
  3. Step 3: Cross multiply
    288.80x = 431.36 × 261.92
  4. Step 4: Simplify right side
    288.80x = 112,981.81
  5. Step 5: Solve for x
    x = 112,981.81/288.80
  6. Step 6: Final answer
    x = 391.21

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.