As seen in example 2, the objective in the problem is to solve for m<B. First, we must add up all of the angles, m <A + m<B + m + <C= 180 because a triangle is equal to 180. Next, plug the numbers in- it then becomes x + 4 + 8x – 4 + 90 = 180. 90 is an important part of the equation because C is a right angle. Then, add like terms- 9x + 90 = 180- and subtract 90 on both sides- 9x = 180. Finally, divide 90 by 9x and x will become 10. However, we are not finished with the problem. Now, we have to initiate step 2- finding out what angle B really is. First, use the equation associated with angle B- 8x – 4. Next, plug in 8 for in to the equation- 8(10) – 4. Then, distribute 8 to 10- 80 – 4. Finally, m < B = 76.
Jillian Pou Geometry Blog 