Question

9. The perimeter of a square is (4x+20)cm. What will be the length of its diagonal?

Answer 1

Answer:

Draw a line BC parallel to AD

Draw a perpendicular line BE on DF

ABCD is a parallelogram.

BC=AD=25cm

CD=AB=60cm

CF=77-CD=17cm

For Δ BCF

perimeter of triangle=(25+26+17)/2

=68/2=34

By Heron's Formula of triangle=√s(s-a)(s-b)(s-c)

=√34(34-25)(34-26)(34-17)

=204cm²

Now area of ΔBCF=1/2xbase x height

=1/2 BExCF204cm²

=1/2x BEx17BE

=408/17

=24cm

Area of Trapezium =1/2(AB+DF)xBE

=1/2(60+77)x24

=1644cm²

Answer 2

Answer:

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Step-by-step explanation:

Given that

Perimeter P=4x+20

If square has a side a, we know that Perimeter P=4a

⇒4a=4x+20

⇒a=44x+20

⇒a=44(x+5)

⇒a=x+5

We know that if a is the side of square, then length od diagonal D=2a

D=2a

Substituting the value of a in this above eqution we get,

D=2(x+5)