Discover the best answers at Westonci.ca, where experts share their insights and knowledge with you. Ask your questions and receive accurate answers from professionals with extensive experience in various fields on our platform. Explore comprehensive solutions to your questions from knowledgeable professionals across various fields on our platform.

In triangle ABC, m∠A=(6x+9)∘, m∠B=(x−8)∘, and the exterior angle at C is 141∘.

What is the measure of angle B?
12∘
20∘
141∘
129∘


Sagot :

mj3mar

Answer:

12°

Step-by-step explanation:

Let's start with the easy first.

We know that m∠C is 39° because together ∠C and the exterior angle equal 180°. And 180 - 141 = 39.

Now, we can use this to find the remaining two angles.

180° - 39° = 141°

So, this means that we can set up m∠A + m∠B = 141°.

6x + 9 + x - 8 = 141

7x + 1 = 141

7x = 140

x = 20

Finally, we can plug in for our x value and find m∠B.

m∠B = x - 8

m∠B = 20 - 8

m∠B = 12°