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Finding the Fourth Proportional to 111.40, 153.72 and 64.79

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Solution

The fourth proportional to 111.40, 153.72 and 64.79 is: 89.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    111.40 : 153.72 = 64.79 : x
  2. Step 2: Convert to fraction form
    111.40/153.72 = 64.79/x
  3. Step 3: Cross multiply
    111.40x = 153.72 × 64.79
  4. Step 4: Simplify right side
    111.40x = 9,958.75
  5. Step 5: Solve for x
    x = 9,958.75/111.40
  6. Step 6: Final answer
    x = 89.40

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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.