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Finding the Fourth Proportional to 20.76, 28.64 and 15

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Solution

The fourth proportional to 20.76, 28.64 and 15 is: 20.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.76 : 28.64 = 15 : x
  2. Step 2: Convert to fraction form
    20.76/28.64 = 15/x
  3. Step 3: Cross multiply
    20.76x = 28.64 × 15
  4. Step 4: Simplify right side
    20.76x = 429.60
  5. Step 5: Solve for x
    x = 429.60/20.76
  6. Step 6: Final answer
    x = 20.69

Related Problems

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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.