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Finding the Fourth Proportional to 128.58, 177.43 and 79.45

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Solution

The fourth proportional to 128.58, 177.43 and 79.45 is: 109.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.58 : 177.43 = 79.45 : x
  2. Step 2: Convert to fraction form
    128.58/177.43 = 79.45/x
  3. Step 3: Cross multiply
    128.58x = 177.43 × 79.45
  4. Step 4: Simplify right side
    128.58x = 14,095.53
  5. Step 5: Solve for x
    x = 14,095.53/128.58
  6. Step 6: Final answer
    x = 109.63

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These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.