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Finding the Fourth Proportional to 90.02, 134.64 and 78.80

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Solution

The fourth proportional to 90.02, 134.64 and 78.80 is: 117.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.02 : 134.64 = 78.80 : x
  2. Step 2: Convert to fraction form
    90.02/134.64 = 78.80/x
  3. Step 3: Cross multiply
    90.02x = 134.64 × 78.80
  4. Step 4: Simplify right side
    90.02x = 10,608.96
  5. Step 5: Solve for x
    x = 10,608.96/90.02
  6. Step 6: Final answer
    x = 117.85

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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.