Construction a quadrilateral ABCD , in which `AB=4cm , BC=3cm ,angleA=75^@ , angleB=80^@ , angleC=120^@`

Explanation

(1) draw a line segment AD =5.5 cm long and bisect it at point M.
(2) M as centre and radius equal MA or MD
draw a semicircle , now A as centre and radius.
5 cm cut an arc at point C on the circumfrence of semicircle. Join C toA and C to D .
You will find angle ACD =90°
(3) now bisect AC at point N . N as centre and radius NA or NC draw a semicircle . A as centre and radius 4 cm cut an arc on the semi circle at point B. Join B to A and B to C. Again you will find angle ABC =90°.
This is your required quadrileteral ABCD.