Question

Please explain steps

Answer 1

122º

Explanation:

The interior angles of a heptagon add to 900º. We can write an equation and solve:

• (12x-9)º+(9x+14)º+(133)º+(10x+9)º+(10x)º+(136)º+(10x+5)º=900º
• Combine like terms, 51xº+288º=900º
• Subtract, 51xº=612º
• Divide, xº=12º

Now that we know x, we can find the measure of ∠B:

• ∠B=9(12)+14=108+14=122º