A) Here, sum of two non-adjacent angles: 52 + 25 = 77
Now, ∠3 = 180 - 77 [ sum of all angles in a triangle is 180 ]
so, ∠3 = 103
Now, ∠3 + ∠4 = 180 [ Supplementary angles ]
So, ∠4 = 180 - ∠3
∠4 = 180 - 103 = 77
∠4 = 77 [ which is sum of two non-adjacent angles ]
....Hence proved.
b) m∠4 = 77
[ Solved in previous section ]
Hope this helps!
The measure of the missing side is 3x^3 +2x - 7y + 9
<h3>Perimeter of a triangle</h3>
The perimeter of a triangle is equal to the sum of all the sides of the triangle. Mathematically;
P = s1 + s2 + s3
where;
s1 = s2 = -8x^3 + 2
P = -13x^3 + 2x - 7y + 3
Substitute the given parameters
-13x^3 + 2x - 7y + 3 = s3. + 2(-8x^3 + 2)
-13x^3 + 2x - 7y + 3 = s3 - 16x^3 -4
s3 = -13x^3 + 2x - 7y + 3 + 16x^3 + 6
s3 = 3x^3 +2x - 7y + 9
Hence the measure of the missing side is 3x^3 +2x - 7y + 9
learn more on perimeter of triangle here: brainly.com/question/24382052
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=3,915
product is use for multiplying