Answer: The third quadrant because it is opposite of the first quadrant
To prove it, you can use the Pythagorean theorem and plug in the numbers. If it equals the same number on both sides it is a Pythagorean triple.
a² + b² = c² (c is the hypotenuse or the longest side/length)
77² + 420² = 427²
5929 + 176400 = 182329
182329 = 182329
It is a Pythagorean triple
Since angle 1 and 2 are supplementary they should equal 180 degrees. So 180-67=113 and since angle 1 and 3 are vertical they are congruent so angle 3 equals 113
D=16.8
d=2 (3w)+2w
16.8=6w+2w
16.8=8w
w=2.1
l=3w
l=3*2.1
l=6.3
a=lw
a=6.3*2.1
a=13.23