Question

in a triangle ABC AB:BC=3:4 BC :AC =5:4
A) If AB=30 degre .what is the length of BC
B ) what is AB:BC:AC​

Answer 1

Answer:

(A) The length of BC  40°

(B) AB : BC : CA = 15 : 20 : 16

Step-by-step explanation:

Given as :

For any Triangle ABC

The ratio are as

AB : BC = 3 : 4

BC : AC = 5 : 4

Or, $\dfrac{AB}{BC}$  = $\dfrac{3}{4}$  × $\dfrac{5}{5}$

So, $\dfrac{AB}{BC}$  = $\dfrac{15}{20}$

And $\dfrac{BC}{AC}$ = $\dfrac{5}{4}$  × $\dfrac{4}{4}$

So , $\dfrac{BC}{AC}$ = $\dfrac{20}{16}$

Therefor the ratio can be written as

AB : BC : CA = 15 : 20 : 16

Let The length of AB = 15 x

The length of BC = 20 x

The length of CA = 16 x

A/Q

AB  = 30°

Or, 15 x = 30°

∴    x = $\dfrac{30}{15}$

  i.e  x = 2°

Put the value of x in BC value

i.e The length of BC = 20 × 2° = 40°

Hence, (A) The length of BC  40°

And      (B) AB : BC : CA = 15 : 20 : 16   Answer