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Finding the Fourth Proportional to 75, 112.50 and 20.90

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Solution

The fourth proportional to 75, 112.50 and 20.90 is: 31.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    75 : 112.50 = 20.90 : x
  2. Step 2: Convert to fraction form
    75/112.50 = 20.90/x
  3. Step 3: Cross multiply
    75x = 112.50 × 20.90
  4. Step 4: Simplify right side
    75x = 2,350.69
  5. Step 5: Solve for x
    x = 2,350.69/75
  6. Step 6: Final answer
    x = 31.34

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1.5x scale

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.