look at the horizontal line in the picture. the degree measure of any line is 180° given there's a perpendicular ray through that horizontal line it's therfore split into two sides both with angle measure of 90°.
given f is 71° then g can be found knowing that both g and f must add to 90°. 71+g=90. g=19°
now look at f again. f and d are what's known as vertical angles and that means that they're angle measures are congruent. therfore the measure of d is 71° d=71°
Finally to find e we notice that angle d and e form a straight line which means both angles measures must add to 180°. therefore e can be found by computing d+e=180
aunaitituitmg our information we know 71+e=180 then e must equal 109° e=109°
