1 MarkQ63. If the centroid of a triangle is $(1, 4)$ and two of its vertices are $(3, -5)$ and $(-7, 4)$, the third vertex is:
(a) $(7, 13)$
(b) $(13, 7)$
(c) $(-7, 13)$
(d) $(5, 9)$
Solution:
$\frac{3 + (-7) + x}{3} = 1 \implies -4 + x = 3 \implies x = 7$
$\frac{-5 + 4 + y}{3} = 4 \implies -1 + y = 12 \implies y = 13$. Vertex is $(7, 13)$. Answer: (a) $(7, 13)$
1 MarkQ64. If the points $(a, 0)$, $(0, b)$, and $(1, 1)$ are collinear, then:
(a) $\frac{1}{a} + \frac{1}{b} = 1$
(b) $a + b = 1$
(c) $ab = 1$
(d) $a - b = 1$
Solution:
Using the intercept form line equation $\frac{x}{a} + \frac{y}{b} = 1$ passing through $(1, 1)$ gives $\frac{1}{a} + \frac{1}{b} = 1$. Answer: (a) $\frac{1}{a} + \frac{1}{b} = 1$
1 MarkQ65. If the points $A(6, 1)$, $B(8, 2)$, $C(9, 4)$, and $D(p, 3)$ are the vertices of a parallelogram taken in order, then the value of $p$ is:
(a) $7$
(b) $8$
(c) $6$
(d) $5$
Solution:
Midpoint of diagonal AC = Midpoint of diagonal BD:
$\left(\frac{6 + 9}{2}, \frac{1 + 4}{2}\right) = \left(\frac{8 + p}{2}, \frac{2 + 3}{2}\right) \implies \frac{6 + 9}{2} = \frac{8 + p}{2} \implies 15 = 8 + p \implies p = 7$. Answer: (a) $7$
1 MarkQ66. The point on the x-axis which is equidistant from $(2, -5)$ and $(-2, 9)$ is:
(a) $(-7, 0)$
(b) $(7, 0)$
(c) $(0, 7)$
(d) $(-2, 0)$
Solution:
Let the point be $(x, 0)$. Equating squared distances to $(2, -5)$ and $(-2, 9)$:
$(x - 2)^2 + (0 - (-5))^2 = (x - (-2))^2 + (0 - 9)^2$
$x^2 - 4x + 4 + 25 = x^2 + 4x + 4 + 81 \implies 29 - 4x = 85 + 4x \implies 8x = -56 \implies x = -7$. Point is $(-7, 0)$. Answer: (a) $(-7, 0)$
1 MarkQ67. The points $(1, 7)$, $(4, 2)$, $(-1, -1)$, and $(-4, 4)$ form a:
(a) Square
(b) Rhombus
(c) Rectangle
(d) Parallelogram
Solution:
All four side lengths calculated via distance formula are equal ($\sqrt{34}$), and diagonals are equal ($\sqrt{68}$), confirming a square. Answer: (a) Square
1 MarkQ68. The ratio in which the line segment joining $(1, -5)$ and $(-4, 5)$ is divided by the x-axis is:
(a) $1 : 1$
(b) $2 : 3$
(c) $3 : 4$
(d) $1 : 2$
Solution:
For the x-axis, $y = 0$. Using section formula: $y = \frac{k(5) + 1(-5)}{k + 1} = 0 \implies 5k - 5 = 0 \implies k = 1$ (Ratio $1 : 1$). Answer: (a) $1 : 1$
1 MarkQ69. If the distance between $(x, -1)$ and $(3, 2)$ is $5$, then $x$ can be:
1 MarkQ72. The points $(3, 0)$, $(6, 4)$, and $(-1, 3)$ form a:
(a) Right-angled isosceles triangle
(b) Equilateral triangle
(c) Scalene triangle
(d) Right-angled scalene triangle
Solution:
Side squares are $25$, $50$, and $25$. Since two sides are equal ($5$) and sum of their squares equals the third side's square ($25 + 25 = 50$), it is a right-angled isosceles triangle. Answer: (a) Right-angled isosceles triangle
1 MarkQ73. The coordinates of the point which divides the join of $(4, -3)$ and $(8, 5)$ in the ratio $3 : 1$ internally are:
1 MarkQ84. The circumcentre of the triangle with vertices $(0, 0)$, $(3, 0)$, and $(0, 4)$ is:
(a) $(1.5, 2)$
(b) $(2, 1.5)$
(c) $(3, 4)$
(d) $(0, 0)$
Solution:
Since it is a right-angled triangle at the origin, the circumcentre is the midpoint of the hypotenuse joining $(3, 0)$ and $(0, 4)$, which is $\left(\frac{3}{2}, \frac{4}{2}\right) = (1.5, 2)$. Answer: (a) $(1.5, 2)$
1 MarkQ85. If the centroid of the triangle formed by $(7, x)$, $(y, -6)$, and $(9, 10)$ is $(6, 3)$, then $(x, y)$ is:
(a) $(5, 2)$
(b) $(2, 5)$
(c) $(-5, -2)$
(d) $(4, 3)$
Solution:
$\frac{7 + y + 9}{3} = 6 \implies 16 + y = 18 \implies y = 2$
$\frac{x - 6 + 10}{3} = 3 \implies x + 4 = 9 \implies x = 5$. Point is $(5, 2)$. Answer: (a) $(5, 2)$
1 MarkQ86. If the vertices of a parallelogram are $(-2, -1)$, $(1, 0)$, $(x, 3)$, and $(1, 2)$, $x$ is:
(a) $4$
(b) $2$
(c) $-2$
(d) $-4$
Solution:
Midpoint of diagonal joining $(-2, -1)$ and $(x, 3)$ equals midpoint of diagonal joining $(1, 0)$ and $(1, 2)$:
$\frac{-2 + x}{2} = \frac{1 + 1}{2} \implies -2 + x = 2 \implies x = 4$. Answer: (a) $4$
1 MarkQ87. The distance of the point $(3, 4)$ from the x-axis is:
(a) $4$
(b) $3$
(c) $5$
(d) $7$
Solution:
Distance from the x-axis is given by the absolute value of the y-coordinate, which is $4$. Answer: (a) $4$
1 MarkQ88. The distance of the point $(3, 4)$ from the y-axis is:
(a) $3$
(b) $4$
(c) $5$
(d) $7$
Solution:
Distance from the y-axis is given by the absolute value of the x-coordinate, which is $3$. Answer: (a) $3$
1 MarkQ89. If the origin is the midpoint of the segment joining $(2, 3)$ and $(x, y)$, then $(x, y)$ is:
(a) $(-2, -3)$
(b) $(2, 3)$
(c) $(0, 0)$
(d) $(-3, -2)$
Solution:
$\frac{2 + x}{2} = 0 \implies x = -2$, $\frac{3 + y}{2} = 0 \implies y = -3$. Point is $(-2, -3)$. Answer: (a) $(-2, -3)$
1 MarkQ90. The area of the triangle with vertices $(0, 0)$, $(4, 0)$, and $(0, 3)$ is:
Solution:
By definition, the origin has coordinates $(0, 0)$. Answer: (a) $(0, 0)$
1 MarkQ97. The distance of the point $(a, b)$ from the origin is:
(a) $\sqrt{a^2 + b^2}$
(b) $a^2 + b^2$
(c) $a + b$
(d) $\sqrt{a + b}$
Solution:
Using the distance formula from $(0, 0)$: $\sqrt{(a - 0)^2 + (b - 0)^2} = \sqrt{a^2 + b^2}$. Answer: (a) $\sqrt{a^2 + b^2}$
1 MarkQ98. If the area of a triangle is zero, the vertices are:
(a) Collinear
(b) Vertices of an equilateral triangle
(c) Vertices of a right triangle
(d) None of these
Solution:
An area of zero means the points lie on the exact same straight line, meaning they are collinear. Answer: (a) Collinear
1 MarkQ99. The ratio in which the origin divides the join of $(1, 1)$ and $(-1, -1)$ is:
(a) $1 : 1$
(b) $2 : 1$
(c) $1 : 2$
(d) $3 : 1$
Solution:
The origin $(0, 0)$ is the exact midpoint of $(1, 1)$ and $(-1, -1)$, which corresponds to the ratio $1 : 1$. Answer: (a) $1 : 1$
1 MarkQ100. If the vertices of a triangle are $(0, 0)$, $(1, 1)$, and $(2, 2)$, the area is:
(a) $0$
(b) $1$
(c) $2$
(d) $3$
Solution:
Since the given points are collinear (lying on the line $y = x$), they do not enclose a triangle, resulting in an area of $0$. Answer: (a) $0$
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English: These model solutions are structured to global academic standards for self-assessment and practice purposes. Students are advised to verify with official textbooks for board examinations.
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