15ᵗʰ

of July 2022

Geometry Therein #1 ( Rolo)

Edexcel International Maths Lent book

gcse

2 .
En 23 B p 365

Q2
(e)

1
opposite interior
angles
on a line corresponding

add to 180°
75° + n = 180° interior
angles up
n = 180 -
75

n =
105°
C >

75° + me = 180° angles on a

straight line add up to 180°

m = 180 -

75 7

]
m = 105° < men
corresponding angles are
equal
L M = 105°

< >

< n = Lo
corresponding angles are
equal
Lo = 105°
< >

< o = < p opposite angles are

eqod
< >
 Chis
(a)

interior to 180°
a + 85° = 180° angles add
up
a = 180-85

a =
95°

< >

Q3 (b)

Corresponding interior

Lc =
114° Corresponding angles are
equal
< >

to 180°
< c + Lb = 180°
interior
angles add up
114° + Lb = 180°

Lb = 180 -114

Lb = 66°

< >
 the to prove that the three
On 9 .
Use
diagram angles in a
triangle add
up
to 180°
.

e e
a
d

Ld = Lb
alternate
angles are
equal
L )

alternate
Le = Lc angles are
equal
< >

L b + L C + La = 180°
*
that each
assuming < would
equal 60° .

L >
 ER 23C p 369

Q5 .

(a)

the sum
82° +27° = La of interior angles =
Enterica
angle
109° = La

a = 109°

< >

Q5 (b)

the sum
20° + 110° = Lb of interior angles =
Enterica
angle
130° = Lb

b = 130°

< >

As (c)

the sum
55° +80° = Lc of interior angles =
Enterica
angle
135° = Lc

C = 135°

< >
⑥
C

pg
,

< A = 30° opposite angles are

eqeal
L >

Ld = Le
opposite angles are
equal
< >
-

angles on a
point add
up
to 360°
LD + Le + L + L = 3600

105° + 105° + LB + LB = 360°

210° + 2B = 360°

2B = 360 -
210

2B =
150°

B = 150
2

< B = 75°

L >

Itta
LA + LB + LC = 180°
sum
of in a
triangle add
up
to 180°

30° + 75°-12C = 180°

105° + LC = 180°

LC = 180 -

105

C = 75°
< >

Triangle DEF is an isosceles

triangle .

>
<
 Edexcel international Mathematics Student book 1
gcse ( a- 1)
A .

In I. p 55

QI .

a + b-+ c = 1800
the sum
of angles in a
triangle add
up
to 180°

L a = 60°

< b = 60° > because it's an

equilateral triangle .

L C = 60°

< >

90° + Le + Ld = 180°
the sum
of angles in a
triangle add
up
to 180°

90° + 60 + Ld = 180°

150° + Ld = 180°

Ld = 180 -
I 50

d = 30°

L )

straight to
Le + L
f = 180° the sum
of angles on a line add
up
180° ]

60° 180°
Lf
+ =

180 60
Lf
-

120°
if
< =

C >

Lf + 12° + L
g
= 180° the sum
of angles in a
triangle add
up
to 180°

120° 12° 180

Lg
+ =
+

132° 180
Lg
=
+

180 132
Lg
-

48°
g
=

L )
3 (b)

81° 67°
the sum
of interior
angles = exterior angle
Ly
+ =

148°
Ly
=

= 1480
Y
L >
 En TE p
56

Q2 (d) A

L A = 60°

Because its equilateral triangle

>

LB = 60° an

L C = 60°

< >

Lb + Lv = 180° the sum

of angles on a
straight line add
up
to 180° ]

60° + Lv = 180°

LV = 180 - 60

V = 120°

< >

L C + Leu = 180° the sum

of angles on a
straight line add
up
to 180° ]
60° + L W = 180°

L W = 180 -
60

Lw = I 20°

< >
Q6 .

LZ 3
y
=

< 2 + 2
y
= 180° the sum
of angles of triangle
a add
up
to 180°

3 2 180°
y
=

y
+

°
I 80
5g
=

I 80 ÷ 5
y
=

°
36
y
=

So ,
LZ = 36 ✗ 3

= 108°

< >
 Complete Mathematics
for Cambridge igcse

I. Ent p 137

at
(8)

Le + Le +
if Lf+ = 180°
the sum
of angles on a
straightline add up
to 180°

2e + 2e + Ze = 180°

be = 180°

Le = 180° :-b

e = 30°

( >
 r

2 >

Mr. Mohammad ,

with the
I
struggled following while
solving my Hw : -

* (Edexcel Igcse maths

Q9 textbook )

proving
that the
angles of a
triangle add up to 180°

( complete
for Cambridge igcse )
Mathematics
* Q1 (part 24)

Lecture
please explain them to me on our next on
Sunday ,
In Sha Allah .

Thank
you
so much
for your effort with me .