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Finding the Fourth Proportional to 31.18, 42.96 and 28.48

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Solution

The fourth proportional to 31.18, 42.96 and 28.48 is: 39.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.18 : 42.96 = 28.48 : x
  2. Step 2: Convert to fraction form
    31.18/42.96 = 28.48/x
  3. Step 3: Cross multiply
    31.18x = 42.96 × 28.48
  4. Step 4: Simplify right side
    31.18x = 1,223.50
  5. Step 5: Solve for x
    x = 1,223.50/31.18
  6. Step 6: Final answer
    x = 39.24

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1.5x scale

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.