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Finding the Fourth Proportional to 64.80, 89.45 and 40.25

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Solution

The fourth proportional to 64.80, 89.45 and 40.25 is: 55.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.80 : 89.45 = 40.25 : x
  2. Step 2: Convert to fraction form
    64.80/89.45 = 40.25/x
  3. Step 3: Cross multiply
    64.80x = 89.45 × 40.25
  4. Step 4: Simplify right side
    64.80x = 3,599.71
  5. Step 5: Solve for x
    x = 3,599.71/64.80
  6. Step 6: Final answer
    x = 55.55

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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.