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Finding the Fourth Proportional to 30.76, 42.48 and 30.70

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Solution

The fourth proportional to 30.76, 42.48 and 30.70 is: 42.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.76 : 42.48 = 30.70 : x
  2. Step 2: Convert to fraction form
    30.76/42.48 = 30.70/x
  3. Step 3: Cross multiply
    30.76x = 42.48 × 30.70
  4. Step 4: Simplify right side
    30.76x = 1,304.14
  5. Step 5: Solve for x
    x = 1,304.14/30.76
  6. Step 6: Final answer
    x = 42.40

Related Problems

Find fourth proportional to 15.38, 21.24 and 15.35
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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.