ExamVeda
Login
Home
81
If angle bisector of a triangle bisects the opposite side, then what type of triangle is it?
Discuss
Answer & Solution
Answer: Option C
Solution:
According to question,
Triangles mcq solution image
AB = AC
BD = DC
The triangle will be isosceles and equilateral triangle
82
If the sides of a right angled triangle are three consecutive integers, then the length of the smallest side is
Discuss
Answer & Solution
Answer: Option A
Solution:
According to question,
Triangles mcq solution image
ABC is a right angle triangle
By using Pythagoras theorem
AC2 = BC2 + AB2
52 = 32 + 42
25 = 9 + 16
25 = 25 (satisfied)
∴ Smallest length of right angle triangle is 3 units
83
In a triangle ABC, BC is produced to D so that CD = AC. If ∠BAD = 111° and ∠ACB = 80°, then the measure of ∠ABC is:
Discuss
Answer & Solution
Answer: Option D
Solution:
According to question,
Triangles mcq solution image
Given :
AC = CD
∠BAD = 111°
∠ACB = 80°
∴ ∠ACD = 180° - 80°
∠ACD = 100°
In isosceles triangle ACD
   ∠ACD + ∠CAD + ∠ADC = 180°
   2∠CAD = 180° - 100°
   ∠CAD = 40°
∴ ∠CAB = 111° - 40° = 71°
∴ ∠ABC = 180° - 71° - 80°
   ∠ABC = 29°
84
In a ΔABC, AB = BC, ∠B = x° and ∠A = (2x - 20)°, Then ∠B is :
Discuss
Answer & Solution
Answer: Option D
Solution:
According to question,
Triangles mcq solution image
Given :
AB = AC
∠C = ∠A = 2x - 20°
∠B = x°
As we know that
∠A + ∠B + ∠C = 180°
(2x - 20)° + x + (2x - 20)° = 180°
5x = 220°
x = 44°
∴ ∠B = 44°
85
If two angles of a triangle are 21° and 38°, then the triangle is :
Discuss
Answer & Solution
Answer: Option C
Solution:
According to question,
Triangles mcq solution image
Given :
∠A = 21°,       ∠C = 38°
As we know that
∠A + ∠B + ∠C
∠B = 180° - 21° - 38°
∠B = 121°
∴ The triangle is obtuse-angled triangle.
86
In ΔPQR, S and T are point on sides PR and PQ respectively such that ∠PQR = ∠PST, If PT = 5 cm, PS = 3 cm and TQ = 3 cm, then length of SR is
Discuss
Answer & Solution
Answer: Option C
Solution:
According to question,
Triangles mcq solution image
Given :
PT = 5 cm
PS = 3 cm
TQ = 3 cm
SR = ?
ΔPQR ∼ ΔPST
Triangles mcq solution image
$$\eqalign{ & \frac{{PR}}{{PT}} = \frac{{PQ}}{{PS}} \cr & \frac{{PR}}{5} = \frac{8}{3} \cr & PR = \frac{{40}}{3} \cr & \therefore SR = PR - PS \cr & SR = \frac{{40}}{3} - 3 \cr & SR = \frac{{40 - 9}}{3} \cr & SR = \frac{{31}}{3}\,{\text{cm}} \cr} $$
87
In a ΔABC, AB = AC and BA is produced to D such that AC = AD. Then the ∠BCD is :
Discuss
Answer & Solution
Answer: Option D
Solution:
According to question,
ABC is an isosceles triangle.
Triangles mcq solution image
∴ ∠C = ∠B = θ
∠CAD = ∠C + ∠B
∠CAD = θ + θ
∠CAD = 2θ
ADC is a isosceles triangle
∠C + ∠D + ∠A = 180°
2∠C = 180° - 2θ°
(∠C = ∠D)
∠C = 90° - θ
∴ ∠BCD = θ + 90 - θ
∠BCD = 90°
88
In ΔABC, two points D and E are taken on the lines AB and BC respectively in such a way that AC is parallel to DE. Then ΔABC and ΔDBE are :
Discuss
Answer & Solution
Answer: Option C
Solution:
According to question,
Give :
'D' and 'E' are the points on AB and BC
Triangles mcq solution image
AC || DE
∠D = ∠A
∠E = ∠C
∴ ΔBDE ∼ ΔBAC
89
If ABC is an equilateral triangle and P, Q, R respectively denote the middle points of AB, BC, CA then
Discuss
Answer & Solution
Answer: Option A
Solution:
According to question,
Triangles mcq solution image
Given : P, Q and R are the mid points of AB, BC and AC
PQ || AC and PQ = $$\frac{1}{2}$$ AC
PR || BC and PR = $$\frac{1}{2}$$ BC
RQ || AB and RQ = $$\frac{1}{2}$$ AB
              (mid point theorem)
∴ ΔPQR is an equilateral triangle
90
In ΔABC, ∠A + ∠B = 65°, ∠B + ∠C = 140°, then find ∠B.
Discuss
Answer & Solution
Answer: Option B
Solution:
According to question,
Triangles mcq solution image
Given :
∠A + ∠B = 65°
∠B + ∠C = 140°
We know that
∠A + ∠B + ∠C = 180°
∠C = 180° - (∠A + ∠B)
∠C = 180° - 65°
∠C = 115°
∠B = 140° - 115°
∠B = 25°