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Finding the Fourth Proportional to 76.77, 105.90 and 64.47

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Solution

The fourth proportional to 76.77, 105.90 and 64.47 is: 88.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.77 : 105.90 = 64.47 : x
  2. Step 2: Convert to fraction form
    76.77/105.90 = 64.47/x
  3. Step 3: Cross multiply
    76.77x = 105.90 × 64.47
  4. Step 4: Simplify right side
    76.77x = 6,827.37
  5. Step 5: Solve for x
    x = 6,827.37/76.77
  6. Step 6: Final answer
    x = 88.93

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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.