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Finding the Fourth Proportional to 64.71, 89.29 and 39.81

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Solution

The fourth proportional to 64.71, 89.29 and 39.81 is: 54.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.71 : 89.29 = 39.81 : x
  2. Step 2: Convert to fraction form
    64.71/89.29 = 39.81/x
  3. Step 3: Cross multiply
    64.71x = 89.29 × 39.81
  4. Step 4: Simplify right side
    64.71x = 3,554.63
  5. Step 5: Solve for x
    x = 3,554.63/64.71
  6. Step 6: Final answer
    x = 54.93

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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.