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Finding the Fourth Proportional to 128.42, 177.26 and 79.30

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Solution

The fourth proportional to 128.42, 177.26 and 79.30 is: 109.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.42 : 177.26 = 79.30 : x
  2. Step 2: Convert to fraction form
    128.42/177.26 = 79.30/x
  3. Step 3: Cross multiply
    128.42x = 177.26 × 79.30
  4. Step 4: Simplify right side
    128.42x = 14,056.72
  5. Step 5: Solve for x
    x = 14,056.72/128.42
  6. Step 6: Final answer
    x = 109.46

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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.