angles in a triangle – missing angles - polperro€¦ · angles in a triangle – missing angles...
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Angles in a triangle – missing angles
1 Matcheachdiagramtothecorrectrule.
Anglesonastraight
linesumto180°
Anglesarounda
pointsumto360°
Anglesinatriangle
sumto180°
Inanisosceles
triangle,twoangles
areequal
Verticallyopposite
anglesareequal
©WhiteRoseMaths2020
2 Workoutthesizesoftheunknownangles.
Givereasonsforeachstageofyourworking.
a)
a= because
b= because
b)
d= because
e= because
f= because
c)
g= because
h= because
i= because
ab
d
ef
g
hi
71°
63°
137°
309°
3 Workoutthesizesoftheanglesmarkedwithletters.
a) e)
p= t=
b) f)
q= u=
c) g)
r= v=
d) h)
s= w=
Talkaboutyourreasonswithapartner.
©WhiteRoseMaths2020
4 Workoutthesizesoftheunknownangles.
a) b)
c= d=
5 Workoutthesizeofanglex.
x=
6 Hereisanisoscelestriangle.
Findtwopossiblesizesofangley.
y= or
84°71°
128°
34°
52°
122°41°
25°
49°
72°
131°
pt
q
u
r
s w
v
87.2°
70.5°
115.6°
99.9°
c
d
37°
48°
61°
y
x