8.0m
7.5m
5.0m
2.5m
Correct answer is D
Using \(V = \pi r^2 h\)
6160 = 22/7 x 28 x 28 x h
\(h = \frac{6160}{22 \times 4 \times 28} \)
\(h = 2.5m \)
How many sides has a regular polygon whose interior angle is 135°?
12
10
9
8
Correct answer is D
p>If each interior angle of the polygon is 135°, then each exterior angle is 180° - 135° = 45°.
Hence, number of sides =
\(\frac{360°}{\text{one exterior angle}}\)
\(\frac{360°}{45°}\)
= 8
Find the value of \(\begin{vmatrix}0 & 3 & 2 \\1 & 7 & 8 \\0 & 5 & 4\end{vmatrix}\).
12
10
-1
-2
Correct answer is D
\(0 \begin{vmatrix}7 & 8 \\5 & 4\end{vmatrix} -3 \begin{vmatrix}1 & 8 \\0 & 4\end{vmatrix} +2 \begin{vmatrix}1 & 7 \\0 & 5\end{vmatrix}\)
= 0(28 - 40) - 3(4 - 0) + 2(5 - 0)
= 0(-12) - 3(4) + 2(5)
= 0 - 12 + 10
= -2
If \(\begin{vmatrix}-x & 12 \\-1 & 4 \end{vmatrix} = - 12\), find x.
-6
-2
3
6
Correct answer is D
\(\begin{vmatrix}-x & 12 \\-1 & 4\end{vmatrix} = - 12\)
-4x - (-1)12 = -12
-4x + 12 = -12
-4x = -12 - 12
-4x = - 24
x = 6
8
5
3
2
Correct answer is C
\(\begin{pmatrix}5 & -6 \\2 & -7\end{pmatrix}\begin{pmatrix} x \\ y \end{pmatrix} = \begin{pmatrix}7 \\-11\end{pmatrix}\)
By matrices multiplication;
5x - 6y = 7 ........(1)
2x - 7y = -11 ......(2)
2 x (1): 10x - 12y = 14 .......(3)
5 x (2): 10x - 35y = -55 ......(4)
(3) - (4): 23y = 69
y = 69/23 = 3