There are 5 ways to test if two figures are congruent, namely;
side-angle-side(SAS)
Angle-side-angle (ASA)
Angle-angle-side(AAS)
Hypotenuse-leg (HL)
3 Sides (SSS)
here we shall focus on SSS. When the three corresponding sides of 2 figures say a triangle have the same length we will conclude that the triangles are congruent by SSS.
Therefore from our choices we can conclude that triangles ABC and ADC are only congruent if the two other side have the same length and BC=DC.
The answer is yes;
B] Yes, but only if BC=DC
The answer is obtuse
a = 4
b = 28
c = 31
If a² + b² > c² - the angle is acute
If a² + b² < c² - the angle is obtuse
If a² + b² = c² - the angle is right
a² + b² = 4² + 28² = 16 + 784 = 800
c² = 31² = 961
800 < 900
a² + b² < c²
Therefore, the angle is obtuse
Use FOIL
28x² -8xy +7xy -2y²
28x² -xy -2y²
