Find the area of the quadrilateral ABCD in which AD = 42 cm , = 900 and is an equilateral triangle having each side equal to 26 cm. Also, find the perimeter of the quadrilateral. [Given = 1.73]
Let us consider a right triangle ABD,
By using Pythagoras theorem in this, we get
AB =
=
=
= 10 cm
We know that,
Area of triangle =
=
= 120 cm2
We also know that,
Area of an equilateral triangle BCD = sq units
=
= 292.37 cm2
Therefore,
Area of quadrilateral ABCD = Area of triangle ABD + Area of triangle BCD
= 120 + 292.37
= 412.37 cm2