In the United States in the 20th century, average life expectancy increased from about 47 years to about 77 years. Find the percent of increase to the nearest percent.

g

step-by-step explanation:

180°

step-by-step explanation:

sum of equilateral triangle=180°

< n=60°

< m=120°°[angle supplementary of equilateral angle]

< m+< r+< x=360°(sum of exterior angle of triangle)

-1/3(x+1)^5

i’m pretty sure this is correct