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Finding the Fourth Proportional to 30.57, 45.75 and 20.91

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Solution

The fourth proportional to 30.57, 45.75 and 20.91 is: 31.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.57 : 45.75 = 20.91 : x
  2. Step 2: Convert to fraction form
    30.57/45.75 = 20.91/x
  3. Step 3: Cross multiply
    30.57x = 45.75 × 20.91
  4. Step 4: Simplify right side
    30.57x = 956.63
  5. Step 5: Solve for x
    x = 956.63/30.57
  6. Step 6: Final answer
    x = 31.29

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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.