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Finding the Fourth Proportional to 90.21, 124.69 and 71.76

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Solution

The fourth proportional to 90.21, 124.69 and 71.76 is: 99.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.21 : 124.69 = 71.76 : x
  2. Step 2: Convert to fraction form
    90.21/124.69 = 71.76/x
  3. Step 3: Cross multiply
    90.21x = 124.69 × 71.76
  4. Step 4: Simplify right side
    90.21x = 8,947.58
  5. Step 5: Solve for x
    x = 8,947.58/90.21
  6. Step 6: Final answer
    x = 99.19

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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.