Answers

2015-09-12T22:46:22+05:30
Let abcd is a parallelogram
ad=34
dc=20
and ac=42
in Δadc
s=34+20+42=48
area of adc=whole in under root(48*14*28*6)
area of adc=336 cm²
now, it is a parallelogram so,
ad=bc=34
dc=ab=20
ac common=42
so area of cba=336 cm²
adding adc and cba=336+336=672cm²
hene area of abcd=672cm²
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2015-09-12T23:37:44+05:30
Ab=bc=34
dc=20 
ac=42
using herons formula  AREA of ΔACD 
√s(s-a)(s-b)(s-c)
√48(48-34)(48-20)(48-42)
√48*14*28*6
=336
AREA of Δabc=336
∵are of parellepgram abcd =336*2=672

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