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Finding the Fourth Proportional to 75.15, 112.72 and 21.05

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Solution

The fourth proportional to 75.15, 112.72 and 21.05 is: 31.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    75.15 : 112.72 = 21.05 : x
  2. Step 2: Convert to fraction form
    75.15/112.72 = 21.05/x
  3. Step 3: Cross multiply
    75.15x = 112.72 × 21.05
  4. Step 4: Simplify right side
    75.15x = 2,372.76
  5. Step 5: Solve for x
    x = 2,372.76/75.15
  6. Step 6: Final answer
    x = 31.57

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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.