(a) Divide \(11111111_{two}\) by \(101_{two}\)
(b) A sector of radius 6 cm has an angle of 105^\circ at the centre. Calculate its:
(i) perimeter ; (ii) area . [Take \(\pi = \frac{22}{7}\)]
Verified Correct Answer: .
Step-by-Step Mathematical Solution
(a) This can either be done using the long division method (easier) or convert everything to base ten and divide, then re-convert to base two.
I'll be using the latter method.
\(11111111_{two} = 1 \times 2^{7} + 1 \times 2^{6} + 1 \times 2^{5} + 1 \times 2^{4} + 1 \times 2^{3} + 1 \times 2^{2} + 1 \times 2^{1} + 1 \times 2^{0}\)
= \(128 + 64 + 32 + 16 + 8 + 4 + 2 + 1 = 255_{ten}\)
\(101_{two} = 1 \times 2^{2} + 0 \times 2^{1} + 1 \times 2^{0} \)
= \(4 + 0 + 1 = 5_{ten}\)
\(\frac{255}{5} = 51_{ten}\)
2
51
2
25 r 1
2
12 r 1
2
6 r 0
2
3 r 0
2
1 r 1
0 r 1
= \(110011_{two}\)
(b)
(i) Length of arc AXB = \(\frac{105}{360} \times 2 \times \frac{22}{7} \times 6cm\)
= \(11cm\)
\(\therefore Perimeter = 6cm + 11cm + 6cm = 23cm\)
(ii) Area of sector = \(\frac{105}{360} \times \frac{22}{7} \times 6cm \times 6cm\)
= \(33 cm^{2}\)
Source: Myschool Past Questions Archive (Record #54552)