class 10 step by step solution
Answers
Answer:
length of AB and AD are 5 and 5√3
and perimeter = 10(1+√3)
Step-by-step explanation:
ABCD is a kite
AB = BC
AD = CD
area of the kite = 25√3
solution :
triangle ABD and BDC are the righht angled triangles
area of triangle ABD = \frac{1}{2}\times base \times height
2
1
×base×height
= \frac{1}{2} \times AD \times AB ..(1)
2
1
×AD×AB..(1)
Similarly
area of triangle BDC = \frac{1}{2} \times CD \times BC ..(2)
2
1
×CD×BC..(2)
but DC = AB and BC = AB
so we can write
area of triangle BDC = \frac{1}{2} \times AD \times AB ..(2)
2
1
×AD×AB..(2)
NOW
area of triangle ABD + area of triangle BDC = area of ABCD
\frac{1}{2} \times AD \times AB +\frac{1}{2} \times AD \times AB = 25\sqrt{3}
2
1
×AD×AB+
2
1
×AD×AB=25
3
\begin{lgathered}AD \times AB = 25\sqrt{3}...(3)\\\end{lgathered}
AD×AB=25
3
...(3)
here BD bisects \angle ADC∠ADC
SO, \begin{lgathered}\angle ADB = 30..(4)\\\end{lgathered}
∠ADB=30..(4)
using trigonometry
\begin{lgathered}tan 30^\circ = \frac{AB}{AD} \\\frac{1}{\sqrt{3} } = \frac{AB}{AD}\\AB =\frac{AD}{\sqrt{3}}\end{lgathered}
tan30
∘
=
AD
AB
3
1
=
AD
AB
AB=
3
AD
On solving we get
AD = 5√3
then
AB = \frac{AD}{\sqrt{3} } = \frac{5\sqrt{3} }{\sqrt{3} } = 5AB=
3
AD
=
3
5
3
=5
NOW
perimeter = AB + BC +CD +DA
= 5+ 5√3+5+5√3
= 10 +10√3
= 10(1+√3)
hence ,
length of AB and AD are 5 and 5√3
and perimeter = 10(1+√3)