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Finding the Fourth Proportional to 64.79, 89.41 and 39.91

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Solution

The fourth proportional to 64.79, 89.41 and 39.91 is: 55.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.79 : 89.41 = 39.91 : x
  2. Step 2: Convert to fraction form
    64.79/89.41 = 39.91/x
  3. Step 3: Cross multiply
    64.79x = 89.41 × 39.91
  4. Step 4: Simplify right side
    64.79x = 3,567.71
  5. Step 5: Solve for x
    x = 3,567.71/64.79
  6. Step 6: Final answer
    x = 55.07

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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.