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Finding the Fourth Proportional to 64.67, 89.21 and 39.76

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Solution

The fourth proportional to 64.67, 89.21 and 39.76 is: 54.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.67 : 89.21 = 39.76 : x
  2. Step 2: Convert to fraction form
    64.67/89.21 = 39.76/x
  3. Step 3: Cross multiply
    64.67x = 89.21 × 39.76
  4. Step 4: Simplify right side
    64.67x = 3,547.05
  5. Step 5: Solve for x
    x = 3,547.05/64.67
  6. Step 6: Final answer
    x = 54.85

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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.