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Finding the Fourth Proportional to 30.48, 42.15 and 28.26

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Solution

The fourth proportional to 30.48, 42.15 and 28.26 is: 39.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.48 : 42.15 = 28.26 : x
  2. Step 2: Convert to fraction form
    30.48/42.15 = 28.26/x
  3. Step 3: Cross multiply
    30.48x = 42.15 × 28.26
  4. Step 4: Simplify right side
    30.48x = 1,191.16
  5. Step 5: Solve for x
    x = 1,191.16/30.48
  6. Step 6: Final answer
    x = 39.08

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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.