Answer:
3. The missing angle is 56°
4. x = 7
Explanation:
3.
We know sum of 3 angles in a triangle is 180°.
Looking at the top triangle, we can figure out the third angle. Let third angle be x:
85 + 35 + x = 180
120 + x = 180
x = 180 - 120
x = 60
The angle "x" and the angle that is missing from the "bottom" triangle in the figure, are vertical angles, and hence, are EQUAL.
So the bottom triangle now has 2 angles, 60 and 64 (given). Let the third angle be y(the one with a question mark). So we can write:
60 + 64 + y = 180
124 + y = 180
y = 180 - 124
y= 56
This is the missing angle.
4.
10x - 5 AND 8x + 9 are vertical angles. They ARE EQUAL.
Thus we can write the equation:
(10x-5) = (8x+9)
10x-8x=9+5
2x=14
x=14/2
x=7
So x = 7