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Finding the Fourth Proportional to 21, 29.10 and 20.49

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Solution

The fourth proportional to 21, 29.10 and 20.49 is: 28.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    21 : 29.10 = 20.49 : x
  2. Step 2: Convert to fraction form
    21/29.10 = 20.49/x
  3. Step 3: Cross multiply
    21x = 29.10 × 20.49
  4. Step 4: Simplify right side
    21x = 596.26
  5. Step 5: Solve for x
    x = 596.26/21
  6. Step 6: Final answer
    x = 28.39

Related Problems

Find fourth proportional to 10.50, 14.55 and 10.25
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Double scale
Find fourth proportional to 22, 30.49 and 21.49
Similar ratio
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.