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Finding the Fourth Proportional to 54, 81 and 45

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Solution

The fourth proportional to 54, 81 and 45 is: 67.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    54 : 81 = 45 : x
  2. Step 2: Convert to fraction form
    54/81 = 45/x
  3. Step 3: Cross multiply
    54x = 81 × 45
  4. Step 4: Simplify right side
    54x = 3,645
  5. Step 5: Solve for x
    x = 3,645/54
  6. Step 6: Final answer
    x = 67.50

Related Problems

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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.