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Finding the Fourth Proportional to 76.63, 105.87 and 53.40

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Solution

The fourth proportional to 76.63, 105.87 and 53.40 is: 73.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.63 : 105.87 = 53.40 : x
  2. Step 2: Convert to fraction form
    76.63/105.87 = 53.40/x
  3. Step 3: Cross multiply
    76.63x = 105.87 × 53.40
  4. Step 4: Simplify right side
    76.63x = 5,653.46
  5. Step 5: Solve for x
    x = 5,653.46/76.63
  6. Step 6: Final answer
    x = 73.78

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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.