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Finding the Fourth Proportional to 90.72, 135.98 and 52.20

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Solution

The fourth proportional to 90.72, 135.98 and 52.20 is: 78.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.72 : 135.98 = 52.20 : x
  2. Step 2: Convert to fraction form
    90.72/135.98 = 52.20/x
  3. Step 3: Cross multiply
    90.72x = 135.98 × 52.20
  4. Step 4: Simplify right side
    90.72x = 7,097.22
  5. Step 5: Solve for x
    x = 7,097.22/90.72
  6. Step 6: Final answer
    x = 78.24

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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.