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Finding the Fourth Proportional to 21.38, 29.58 and 20.58

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Solution

The fourth proportional to 21.38, 29.58 and 20.58 is: 28.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.38 : 29.58 = 20.58 : x
  2. Step 2: Convert to fraction form
    21.38/29.58 = 20.58/x
  3. Step 3: Cross multiply
    21.38x = 29.58 × 20.58
  4. Step 4: Simplify right side
    21.38x = 608.76
  5. Step 5: Solve for x
    x = 608.76/21.38
  6. Step 6: Final answer
    x = 28.47

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1.5x scale

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.