descending order of
3. In AABC, BC is produced to D so that
AB = AC=CD. If ZBAC = 720, find the angles
of AABD and arrange its sides in ascending
order of length.
720
B
D
С
98
ICSE Mat
Answers
Answer:
Step-by-step explanation:
∠ABO=37
o
∠ACB=180
o
−117
o
=63
o
∠OCB=63/2
BOC=180−37−31.5=180
68.5
111.5
o
BC>OC>OB (length).
Step-by-step explanation:
In the above ∆ABC.
∆ABC is an isosceles triangle.
Because,
AB=AC
We know that in an isosceles triangle equal sides are opposite angles are also equal.
Now,
Let angle B in ∆ABC be x.
Then,
angle B = angle C
x° = x°
using angle sum property
72° + x° + x°
2x° = 180° - 72° = 108°
x° = 108°/2 = 54°
x° = 54° = angle ABC
Now, going to ∆ADC.
It is an isosceles triangle.
Because,
AC = CD
We know that in an isosceles triangle equal sides are opposite angles are also equal.
Now,
angle CAD = angle CDA
Let angle CAD = y°.
y° = y°
Taking only ∆ABC extending the line BC to CD.
using the property
exterior angle = sum of two interior opposite angles.
angle ACD = angle CAB + angle ABC
angle ACD = 72° + 59°
angle ACD = 131°.
Using the sum property
131° + y° + y° = 180°
2y° = 180° - 131° = 49°
y° = 49°/2 = 24.5° = angle CAD = angle CDA
Now,
angle ABC = 54°
angle DAB = angle CAB + angle CAD
angle DAB = 72° + 24.5° = 96.5°
angle ADB = 24.5°
Hope it helps you...
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