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Finding the Fourth Proportional to 64.79, 89.64 and 55.56

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Solution

The fourth proportional to 64.79, 89.64 and 55.56 is: 76.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.79 : 89.64 = 55.56 : x
  2. Step 2: Convert to fraction form
    64.79/89.64 = 55.56/x
  3. Step 3: Cross multiply
    64.79x = 89.64 × 55.56
  4. Step 4: Simplify right side
    64.79x = 4,980.40
  5. Step 5: Solve for x
    x = 4,980.40/64.79
  6. Step 6: Final answer
    x = 76.88

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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.