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Finding the Fourth Proportional to 64.40, 96.61 and 18.75

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Solution

The fourth proportional to 64.40, 96.61 and 18.75 is: 28.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.40 : 96.61 = 18.75 : x
  2. Step 2: Convert to fraction form
    64.40/96.61 = 18.75/x
  3. Step 3: Cross multiply
    64.40x = 96.61 × 18.75
  4. Step 4: Simplify right side
    64.40x = 1,810.86
  5. Step 5: Solve for x
    x = 1,810.86/64.40
  6. Step 6: Final answer
    x = 28.12

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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.