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Finding the Fourth Proportional to 22.80, 31.38 and 21.36

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Solution

The fourth proportional to 22.80, 31.38 and 21.36 is: 29.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    22.80 : 31.38 = 21.36 : x
  2. Step 2: Convert to fraction form
    22.80/31.38 = 21.36/x
  3. Step 3: Cross multiply
    22.80x = 31.38 × 21.36
  4. Step 4: Simplify right side
    22.80x = 670.28
  5. Step 5: Solve for x
    x = 670.28/22.80
  6. Step 6: Final answer
    x = 29.40

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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.