Question

If perimeter of a ∆ABC is 12.2 cm & AB+BC=7.9 then find Length (AC).
A)5.5
B)4.3
C)20.1
D)4.5​

Answer 1

Given:-

In $\triangle$ABC

Perimeter=12.2cm

AB+BC=7.9cm

To find:-

Length of AC

Solution:-

As we know that

if the sides of a triangle are =a,b and c

then

${\boxed{perimeter=a+b+c}}$

Substitute the values

${:}\longrightarrow$$AB+BC+AC=12.2$

${:}\longrightarrow$$7.9+AC=12.2$

${:}\longrightarrow$$AC=12.2-7.9$

${:}\longrightarrow$${\underline{\boxed{\bf {{\overline{AC}}=4.3cm}}}}$

Learn more

if sides of a triangle are a,b and c

${\boxed{Semiperimeter=s={\dfrac {a+b+c}{2}}}}$

${\boxed{Area={\sqrt {s (s-a)(s-b)(s-c)}}}}$