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Finding the Fourth Proportional to 15.81, 21.96 and 15.60

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Solution

The fourth proportional to 15.81, 21.96 and 15.60 is: 21.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.81 : 21.96 = 15.60 : x
  2. Step 2: Convert to fraction form
    15.81/21.96 = 15.60/x
  3. Step 3: Cross multiply
    15.81x = 21.96 × 15.60
  4. Step 4: Simplify right side
    15.81x = 342.58
  5. Step 5: Solve for x
    x = 342.58/15.81
  6. Step 6: Final answer
    x = 21.67

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.