Question

the adjacent sides of paralellogram abcd are ab= 34 cm bc= 20 cm daigonal=42 cm. find the area of paralellogram

Answer 1

AB = 34 cm    BC = 20 cm      AC = 42  cm


s = (34+20+42)/2 = 48 cm


Area of triangle ABC

    = √[s (s-a) (s-b)(s-c) ] 

    = 6 * 4 * 14 cm²


Area of parallelogram is twice the area of triangle ABC.


Alternate Method :


consider the triangle ABC
AB=34
BC=20
CA=42
=>S=(34+20+42)/2
       =48

remember that area of a triangle=√s(s-a)(s-b)(s-c)
                                             =√48*14*28*6
                                              =336cm²

area of parallelogram=2*336=672cm²

Hope This Helps :)