Hi, could you please help me to calculate the height of the trapezium in question no 4 

Q 4. In quadrilateral ABCD, AB=10 cm, BC= 6 cm, CD= 2.8 cm, DA = 6 cm and its diagonals are 8 cm  each.
(i) Are ADB and ACB right angles?
(ii) Is ABCD a trapezium? If yes, find its height.
(iii) Find the area of the quadrilateral.


Dear student,


Construction: Draw DE and CF perpendicular to AB.Given: CD=2.8 cm and AB=10 cmSince CD=2.8 cm EF=2.8 cmNow, AB-EF=10-2.8=7.2 cmAE=EF=7.22=3.6 cm In DAEBy pythagoras theoremAD2=DE2+AE262=DE2+3.6236=DE2+12.96DE2=36-12.96DE2=23.04DE=±4.8 cm      (neglecting -ve value as length can't be -ve)Thus the height of trapezium is 4.8 cm

Regards

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