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Finding the Fourth Proportional to 128.32, 177.09 and 76.57

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Solution

The fourth proportional to 128.32, 177.09 and 76.57 is: 105.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.32 : 177.09 = 76.57 : x
  2. Step 2: Convert to fraction form
    128.32/177.09 = 76.57/x
  3. Step 3: Cross multiply
    128.32x = 177.09 × 76.57
  4. Step 4: Simplify right side
    128.32x = 13,559.78
  5. Step 5: Solve for x
    x = 13,559.78/128.32
  6. Step 6: Final answer
    x = 105.67

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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.