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Finding the Fourth Proportional to 128.90, 177.88 and 70.67

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Solution

The fourth proportional to 128.90, 177.88 and 70.67 is: 97.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.90 : 177.88 = 70.67 : x
  2. Step 2: Convert to fraction form
    128.90/177.88 = 70.67/x
  3. Step 3: Cross multiply
    128.90x = 177.88 × 70.67
  4. Step 4: Simplify right side
    128.90x = 12,571.05
  5. Step 5: Solve for x
    x = 12,571.05/128.90
  6. Step 6: Final answer
    x = 97.53

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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.