Answer:
3. 43.96 cm
4. 81.64 ft
Explanation:
3. The formula for the circumference of a circle in terms of radius is ...
C = 2πr
When π is approximated by 3.14, this becomes ...
C ≈ 6.28r
The only answer choice even close to 6.28×(7 cm) is the one shown above.
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4. The formula for the circumference of a circle in terms of diameter is ...
C = πd
When π is approximated by 3.14, this becomes ...
C ≈ 3.14d
The only answer choice anywhere close to 3.14×(26 ft) is the one shown above.
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Comment on the solution
For questions like these, you only need to be able to estimate the answer to 1 or 2 significant digits. The answer choices are not so close together as to cause any confusion.
6×7 = 42, so the answer will be a few more than 42.
3×26 = 78, so the answer will be within a few numbers larger than that.
In each case, the answer is the largest value on the list. The other choices differ by a factor of 2, so aren't even close.