Find the missing angle in a the triangles given below.
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
Problem 1 :
Solution :
<A+<B+<C = 180
Given <A = x, <B = 2x and <C = 90
x+2x+90 = 180
3x+90 = 180
3x = 180-90
3x = 90
x = 90/3
x = 30
So, <A = 30 and <B = 60.
Problem 2 :
<D + <E + F = 180 ----(1)
Since it is isosceles triangle, <E = <F and <D = 90
Let <E = x
90 + x + x = 180
2x+90 = 180
Subtracting 90 on both sides, we get
2x = 90
Divide by 2 on both sides, we get
x = 90/2
x = 45
Problem 3 :
Solution :
<T = 42, <U = 42, <V = ?
<U + <V + <T = 180
42 + <V + 42 = 180
<V + 84 = 180
Subtracting by 84 on both sides, we get
<V = 96
Problem 4 :
Solution :
Vertically opposite angles are equal. So <2 = 40.
<1 + 40 + 90 = 180
<1 + 130 = 180
<1 = 50
<3 + <2 + 95 = 180
<3+40 = 180
<3 = 140
Problem 5 :
Solution :
In small triangle the indicated angle is 90 degree.
Using exterior angle theorem,
56+45 = 50 + <2
<2 = 101-50
<2 = 51
<1 + <2 + 50 = 180
<1+51+50 = 180
<1+101 = 180
<1 = 180-101
<1 = 79
In small triangle,
<2+<3+90 = 180
51 + <3 + 90 = 180
<3 = 180-141
<3 = 39
Problem 6 :
Solution :
By using exterior angle theorem,
x+31 = 2x-8
2x - x = 31 + 8
x = 39
Problem 7 :
Solution :
Using exterior angle theorem,
10x+9 = 7x+1+38
10x-7x = 39 - 9
3x = 30
x = 10
Question 8 :
Solution :
Sum of interior angles of a triangle
x + 2x-21 + 90 = 180
3x+69 = 180
Subtracting 69 on both sides, we get
3x = 180-69
3x = 111
Dividing by 3 on both sides, we get
x = 111/3
x = 37
Question 9 :
Solution :
Sum of interior angle of triangle = 180
x+x+72 = 180
Subtracting 72 on both sides
2x = 180-72
2x = 108
Dividing by 2 on both sides
x = 54
Question 10 :
Solution :
Since it is isosceles triangle, the angle formed by equal sides will be equal.
x+35+35 = 180
x+70 = 180
Subtracting 70 on both sides
x = 180-70
x = 110
Apart from the stuff given above, if you need any other stuff in math, please use our google custom search here.
Kindly mail your feedback to v4formath@gmail.com
We always appreciate your feedback.
©All rights reserved. onlinemath4all.com
Aug 07, 24 08:40 AM
Aug 07, 24 08:09 AM
Aug 03, 24 01:18 PM