Question

If a triangle with sides a= 8 b=10 and c =12 then angle C
A)2A
B)3A
C)A/2
D)3A/2

Answer 1

Answer:

Here, we are given: a=1, b=3 and `C=60^@`

We know,

`cosC` = `(a^2+b^2-c^2)`/`(2ab)`

As C =` 60^@`, we can rewrite the above equation as:

`1/2` = `(a^2+b^2-c^2)`/`(2ab)`

Putting a=1 and b=3, in the above equation:

`1/2` = `(1+9-c^2)`/`6`

`c^2 = 7`

Now, from sine formula:

`b/sinB = c/sinC`

`sin^2B` = `b^2``sin^2C/c^2`

Now,putting b= 3, C = `60^@` and `c^2 = 7`

`sin^2B = (9**3)/(7**4) = 27/28`

Step-by-step explanation:

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