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Finding the Fourth Proportional to 64.80, 89.81 and 64.05

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Solution

The fourth proportional to 64.80, 89.81 and 64.05 is: 88.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.80 : 89.81 = 64.05 : x
  2. Step 2: Convert to fraction form
    64.80/89.81 = 64.05/x
  3. Step 3: Cross multiply
    64.80x = 89.81 × 64.05
  4. Step 4: Simplify right side
    64.80x = 5,752.01
  5. Step 5: Solve for x
    x = 5,752.01/64.80
  6. Step 6: Final answer
    x = 88.77

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.