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Finding the Fourth Proportional to 42.68, 64.00 and 13.78

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Solution

The fourth proportional to 42.68, 64.00 and 13.78 is: 20.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.68 : 64.00 = 13.78 : x
  2. Step 2: Convert to fraction form
    42.68/64.00 = 13.78/x
  3. Step 3: Cross multiply
    42.68x = 64.00 × 13.78
  4. Step 4: Simplify right side
    42.68x = 882.02
  5. Step 5: Solve for x
    x = 882.02/42.68
  6. Step 6: Final answer
    x = 20.67

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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.