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Finding the Fourth Proportional to 90.30, 124.50 and 77.75

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Solution

The fourth proportional to 90.30, 124.50 and 77.75 is: 107.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.30 : 124.50 = 77.75 : x
  2. Step 2: Convert to fraction form
    90.30/124.50 = 77.75/x
  3. Step 3: Cross multiply
    90.30x = 124.50 × 77.75
  4. Step 4: Simplify right side
    90.30x = 9,679.88
  5. Step 5: Solve for x
    x = 9,679.88/90.30
  6. Step 6: Final answer
    x = 107.20

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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.