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Finding the Fourth Proportional to 77.64, 107.13 and 51.78

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Solution

The fourth proportional to 77.64, 107.13 and 51.78 is: 71.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.64 : 107.13 = 51.78 : x
  2. Step 2: Convert to fraction form
    77.64/107.13 = 51.78/x
  3. Step 3: Cross multiply
    77.64x = 107.13 × 51.78
  4. Step 4: Simplify right side
    77.64x = 5,547.19
  5. Step 5: Solve for x
    x = 5,547.19/77.64
  6. Step 6: Final answer
    x = 71.45

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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.