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12. Distance formula =root (x1-x2)^2 +(y1-y2)^2
Ans is option a
13.option b
14.option a
15 option d
16 option b
17 option b
18 option a
19 option d
20. Option a
11.
→ cos 60° = x
Value of cos 60° = ½
→ ½ = x
Hence, value of x is ½.
12.
Given : A(0,8) & B(0,-6)
To find : d(A, B)
Solution : Using distance formula
d(A, B) = 14 units
13.
To find : Value of tanθ+cotθ
Solution : tanθ+cotθ
we know,
- tanθ=sinθ/cosθ
- cotθ=cosθ/sinθ
= tanθ+cotθ
= sinθ/cosθ + cosθ/sinθ
Taking LCM
= sin²θ+cos²θ/sinθcosθ
Using identity : sin²θ+cos²θ = 1
= 1/sinθcosθ
- 1/sinθ=cosecθ
- 1/cosθ=secθ
= (1/sinθ)×(1/cosθ)
= (cosecθ)×(secθ)
= cosecθsecθ
= secθcosecθ
14.
Given: XY || BC
Solution :
XY || BC & AB is transversal
∠AXY=∠ABC[corresponding angles]
XY || BC & AC is transversal
∠AYX = ∠ACB [corresponding angles]
In ∆AXY & ∆ABC
∠AXY=∠ABC[corresponding angles]
∠AYX = ∠ACB [corresponding angles]
∠XAY=∠BAC [common angle]
By AAA similarity criteria.
∆AXY ∼ ∆ABC
Similarly, ∆AYX∼ ∆ACB [as corresponding angles are equal to each other.]
15.
Given:QR = 6√3
∠Q=90°
∠R=30°
∠P=60°
To find : PR
Solution:
In ∆PQR,
QR is a base & PR is hypotenuse.
Also,
For θ = 30°
→cosθ= adjacent side(base)/hypotenuse
→cos 30° = QR/PR
→√3/2 = 6√3/PR
→PR = 6√3/(√3/2)
→PR = (6√3 × 2)/√3
→ PR = 12√3/√3
→ PR = 12
16.
m(arc AXB) = 100°
∠AOB = 100°
∠APB=½∠AOB
∠APB=½(100°)
∠APB=50°
i.e. m∠APB=50°
17.
- Four common tangents can be drawn to two disjoint circles.
- The tangents can be either direct or transverse.
Refer attachment for figure
18.
When a line is divided into two sections
First section : Second section = m:n
Point 1 of line segment(x1,y1)
Point 2 of line segment(x2,y2)
Section Formula
x = mx2+nx1/m+n, y = my2+ny1/m+n
19.
sinθ=7/25
cosθ=?
we know, sinθ = opposite side(perpendicular)/hypotenuse
& cosθ=adjacent side(base)/hypotenuse
By Pythagoras property
H²=B²+P²
25²=B²+7²
625=B²+49
B²=625-49
B²=576
B=√576
B=24
→cosθ=adjacent side(base)/hypotenuse
→cosθ=24/25
20.
∆1 ∼∆2
A(∆1)=3A(∆2)
S1 : S2 =?
When two triangles are similar, square of sides in ratio is equal to ratio of their areas
ar(∆1) / ar(∆2) = (S1/S2)²
3A(∆2) / A(∆2) = (S1/S2)²
3(∆2) / 1(∆2) = (S1/S2)²
3 / 1 = (S1/S2)²
(S1/S2)² = 3/1
(S1/S2) = √(3/1)
(S1/S2) = √3 /√1
(S1/S2) = √3 /1
S1:S2 = √3 : 1