Question

find the base of an isosceles triangle whose area is 12 CM square and one of equal sides is 5 cm .​

Answer 1

Answer:

Let equal sides be (a)=5cm and base (b)=?

Area of an isosceles triangle=12sq.cm

Area of an isosceles triangle=  

4

b

​

 

4a  

2

−b  

2

 

​

 

12=  

4

b

​

 

4×(5)  

2

−b  

2

 

​

 

48=b  

100−b  

2

 

​

 

Squaring both sides  

2304=b  

2

(100−b  

2

)

or  b  

4

−100b  

2

+2304=0

or  b  

4

−64b  

2

−36b  

2

+2304=0

or  b  

2

(b  

2

−64)−36(b  

2

−64)=0

or  (b  

2

−64)(b  

2

−36)=0

either (b  

2

−64)=0⇒b  

2

=64⇒b=±8

or (b  

2

−36)=0⇒b  

2

=36⇒b=±6

Hence base=8cm, or 6cm.

Step-by-step explanation: