solve the question in attachment.
Answers
Given vertices are A(-5,7), B(-4,-5), C(-1,-6), D(4,5).
Area of Quadrilateral ABCD = Area of Δ ABD + ΔBCD.
Finding Area of ΔABD:
We know that Area of ΔABC = (1/2)[x1(y2 - y3) + x2(y3 - y1) + x3(y1 - y2)]
Here,
(i) (x1,y1) = (-5,7)
(ii) (x2,y2) = (-4,-5)
(iii) (x3,y3) = (4,5).
Now,
Area of ΔABC = (1/2)[(-5)(-5 - 5) + (-4)(5 - 7) + 4(7 + 5)]
= > (1/2)[50 + 8 + 48]
= > 106/2
= > 53.
Finding Area of ΔBCD:
We know that Area of triangle ΔBCD = (1/2)[x1(y2 - y3) + x2(y3 - y1) + x3(y1 - y2)
Here,
= > (x1,y1) = (-4,-5)
= > (x2,y2) = (-1,-6)
= > (x3,y3) = (4,5).
Now,
Area of ΔBCD = (1/2)[(-4)(-6 - 5) + (-1)(5 + 5) + (4)(-5 + 6)]
= > (1/2)[44 - 10 + 4]
= > (1/2)[38]
= > 38/2
= > 19.
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Therefore,
= > Area of Quadrilateral ABCD = Area of ΔABD + Area of ΔBCD
= > 53 + 19
= > 72 sq.units.
Hope this helps!