Question

Given: △ABC is an isosceles triangle,

Answer 1

Answer:

Perimeter of △BDC=Sum of all the sides=BD+DC+CB=15+15+15=45

Step-by-step explanation:

Given ΔABC is an isosceles triangle, thus, AB=BC=x and AC=12,

perimeter of  △ABC is=42

⇒x+x+12=42

⇒2x=30

⇒x=15

Thus, AB=BC=15

Now, △BDC is an equilateral triangle therefore BD=DC=BC=x

Since, x=15, therefore BD=DC=BC=15

Now, Perimeter of △BDC=Sum of all the sides=BD+DC+CB=15+15+15=45