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Finding the Fourth Proportional to 30.99, 42.82 and 30.77

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Solution

The fourth proportional to 30.99, 42.82 and 30.77 is: 42.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.99 : 42.82 = 30.77 : x
  2. Step 2: Convert to fraction form
    30.99/42.82 = 30.77/x
  3. Step 3: Cross multiply
    30.99x = 42.82 × 30.77
  4. Step 4: Simplify right side
    30.99x = 1,317.36
  5. Step 5: Solve for x
    x = 1,317.36/30.99
  6. Step 6: Final answer
    x = 42.51

Related Problems

Find fourth proportional to 15.50, 21.41 and 15.38
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Double scale
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Similar ratio
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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.