Answer:
B, C, 45°
Step-by-step explanation:
16.
B. If two figures are congruent then they are similar too because the corresponding angles are congruent and the sides are in proportion (1 to 1 is the proportion if the similar triangles are congruent)
17.
The sum of interior angles in a quadrilateral must be 360°
77+90+6x+8 +9x-10 = 360, add interior angles of the quadrilateral
6x+9x +77+90+8-10 = 360, group like terms
15x +165 = 360, combine like terms
15x = 360 -165, subtract 165 from both sides
15x = 195, divide both sides by 15
x= 13
∡ E = 6x + 8 = 6*13 +8 = 78 +8 = 86 (answer C)
18.
Ratio of angles of a triangle are 3:4:5 and we know that the sum of angles have to be 180°
3x+4x+5x = 180, to keep the proportions we need to find x
12x = 180, add like terms
x= 15, divide both sides by 12
3*x : 4*x : 5*x , the proportion that is given
3*15: 4*15: 5*15, the proportion of our angles
45: 60: 75, the angles that are in proportion 3:4:5 and add up to 180°
The smallest angle is 45°
