Question

In the figure, seg AB || seg DC,m angle C=90°.If l (AB)=50 cm, l (CD) =55 cm, l (BC)=12 cm, find the perimeter of the given figure in cm.

Answer 1

Answer:

We can find out the area of triangle ADB

so height for this triangle wud be equal to the height of trapezium.

so we get height = 12cm.

now we can easily get to CD=7cm

and we know area of trapezium =1/2*(AB+CD)*HEIGHT

NOW,1/2*(25+7)*12 = 192 cm.

how to get CD=7 cm

when we will drop two perpendicular lines from D to AB as point E and from C to AB as point F.

So,we can see that EF = CD (as the line drawns were perpendicular)

Now In triangleADE,

We know AD=15 and DE=12

So we can easily find AE = 9

Similarly from triangleBCF,

we will get BF = 9cm

therefore,EF = AB -(AE+BF) = 25 - 18 =7cm.

Hope it Helps.:)