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Find the perimeter and area of the quadrilateral ABCD in which AB = 17cm, AD = 9cm, CD = 12cm, =900 and AC = 15cm.
By using Pythagoras theorem in right triangle ABC, we get
BC=
=
=
=
= 8 cm
Let us first find out the perimeter of the given quadrilateral
Perimeter of quadrilateral ABCD = 17 + 9 + 12 + 8 = 46 cm
We know that,
Area of triangle ABC =
=
=
= 60 cm2
Now,
For area of triangle ACD, we have
a = 15 cm
b = 12 cm
And,
c = 9 cm
Therefore,
s =
=
= 18 cm
Now,
Area of triangle ACD =
=
=
=
= 18 × 3
= 54 cm2
Therefore,
Area of quadrilateral ABCD = Area of triangle ABC + Area of triangle ACD
= 60 + 54
= 114 cm2