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Finding the Fourth Proportional to 70.79, 105.98 and 56.21

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Solution

The fourth proportional to 70.79, 105.98 and 56.21 is: 84.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    70.79 : 105.98 = 56.21 : x
  2. Step 2: Convert to fraction form
    70.79/105.98 = 56.21/x
  3. Step 3: Cross multiply
    70.79x = 105.98 × 56.21
  4. Step 4: Simplify right side
    70.79x = 5,956.32
  5. Step 5: Solve for x
    x = 5,956.32/70.79
  6. Step 6: Final answer
    x = 84.15

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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.