Welcome :: Homework Help and Answers :: Mathskey.com
Welcome to Mathskey.com Question & Answers Community. Ask any math/science homework question and receive answers from other members of the community.

13,435 questions

17,804 answers

1,438 comments

774,968 users

solution of an oblique triangle with two sides equal.

0 votes
where the included angle is 95 and two sides are 30.
asked Mar 11, 2014 in TRIGONOMETRY by angel12 Scholar

1 Answer

0 votes

An oblique triangle is any triangle that is not a right triangle.

To solve the triangle ,we need to find two angles and one side.

We assume the given angle is angle A = 95°

The equal sides are b = 30 , c = 30.

Aplly law of Cosines

a2 = b2+ c2- 2bc CosA

a2= 302 + 302 -2(30)(30)Cos (95°)

a2 = 900 + 900 - 1800 Cos (95°)

a2 = 1800  -1800(-0.087)

a2 = 1800 + 156.6

a2 = 1956.6

a = 44.23

Now we use the The Law of Sines to find the smaller of the other two angles.

Law of Sines SinA/a = SinB/b = SinC/c.

Now we use SinB/b = SinA/a

SinB/30 = Sin(95°)/44.23

SinB/30 = 0.99/44.23

SinB /30 = 0.022

SinB  = 0.022*30

SinB  = 0.66

B  = Sin-1 (0.66)

B  = 41.29°

Now we find angle C , which is easy using 'angles of a triangle add to 180°.

C   = 180° - (41.29°+ 95°)

C  =  43.71°

 B  = 41.29°, C  = 43.71° and Side a = 44.23.

 

answered Apr 8, 2014 by david Expert

Related questions

asked May 6, 2015 in TRIGONOMETRY by anonymous
...