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Finding the Fourth Proportional to 288.21, 432.31 and 71.78

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Solution

The fourth proportional to 288.21, 432.31 and 71.78 is: 107.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    288.21 : 432.31 = 71.78 : x
  2. Step 2: Convert to fraction form
    288.21/432.31 = 71.78/x
  3. Step 3: Cross multiply
    288.21x = 432.31 × 71.78
  4. Step 4: Simplify right side
    288.21x = 31,030.85
  5. Step 5: Solve for x
    x = 31,030.85/288.21
  6. Step 6: Final answer
    x = 107.67

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.