84.2k views
0 votes
Please help! i cant solve it​

Please help! i cant solve it​-example-1

1 Answer

4 votes

a ≈ 5.2, B ≈ 50°, C ≈ 95°

Solution:

Given data:

A = 35°, b = 7, c = 9

Using cosine law,


a^(2)=b^(2)+c^(2)-2 b c \cos A


a^(2)=7^(2)+9^(2)-2 (7)(9) \cos 35^\circ


a^(2)=49+81-126 (0.82)


a^(2)=26.68

Taking square root on both sides.

a ≈ 5.2

Using sine law,


$(\sin A)/(a) =(\sin B)/(b)


$(\sin 35^\circ)/(5.2) =(\sin B)/(7)

Multiply by 7 on both sides.


$(0.5735)/(5.2)* 7 =\sin B

Switch the sides.

Sin B = 0.772


B=\sin^(-1)0.772

B ≈ 50°

Sum of all the angles of a triangle = 180°

A + B + C = 180°

35° + 50° + C = 180°

85° + C = 180°

C = 180° - 85°

C = 95°

Hence a ≈ 5.2, B ≈ 50°, C ≈ 95°.

User SixDegrees
by
8.2k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories