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Finding the Fourth Proportional to 90.21, 124.26 and 76.39

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Solution

The fourth proportional to 90.21, 124.26 and 76.39 is: 105.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.21 : 124.26 = 76.39 : x
  2. Step 2: Convert to fraction form
    90.21/124.26 = 76.39/x
  3. Step 3: Cross multiply
    90.21x = 124.26 × 76.39
  4. Step 4: Simplify right side
    90.21x = 9,492.22
  5. Step 5: Solve for x
    x = 9,492.22/90.21
  6. Step 6: Final answer
    x = 105.22

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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.