What is the measure of angle 3? Sorry the question got cut off

142

Step-by-step explanation:

angle <3 is supplementary to 5x + 3

5x + 3 + 21x - 5 = 180 (because two angles are supplementary as well)

26x  - 2 = 180 add 2 to both sides

26x = 182 divide both sides by 26

x = 7

<3 + 5x + 3 = 180 replace x with 7 and rewrite equation

<3 + 38 = 180 subtract 38 from both sides

<3 = 142

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.

d. bc = 12 and ef = 16

step-by-step explanation:

we are given that δabc : δdef such that .

also, it is given that

so, from the options, we need that .

a.

b.

c.  

d.

as, we can see that only option d gives the same ratio as i.e. .

hence, the possible lengths are bc = 12 and ef = 16.