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Finding the Fourth Proportional to 21.51, 29.69 and 20.76

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Solution

The fourth proportional to 21.51, 29.69 and 20.76 is: 28.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.51 : 29.69 = 20.76 : x
  2. Step 2: Convert to fraction form
    21.51/29.69 = 20.76/x
  3. Step 3: Cross multiply
    21.51x = 29.69 × 20.76
  4. Step 4: Simplify right side
    21.51x = 616.26
  5. Step 5: Solve for x
    x = 616.26/21.51
  6. Step 6: Final answer
    x = 28.65

Related Problems

Find fourth proportional to 10.76, 14.84 and 10.38
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Double scale
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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.