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Finding the Fourth Proportional to 47.76, 71.48 and 42.90

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Solution

The fourth proportional to 47.76, 71.48 and 42.90 is: 64.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.76 : 71.48 = 42.90 : x
  2. Step 2: Convert to fraction form
    47.76/71.48 = 42.90/x
  3. Step 3: Cross multiply
    47.76x = 71.48 × 42.90
  4. Step 4: Simplify right side
    47.76x = 3,066.33
  5. Step 5: Solve for x
    x = 3,066.33/47.76
  6. Step 6: Final answer
    x = 64.21

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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.