Answer:
See Explanation
Step-by-step explanation:
See attachment for illustration
(a) Right triangle
The sum of [tex]angles[/tex] in a [tex]right[/tex] [tex]triangle[/tex]is:
[tex]x + y + 90 = 180[/tex]
Subtract 90 from bot sides
[tex]x + y = 90[/tex]
Make x the subject
[tex]x = 90 - y[/tex]
Make y the subject
[tex]y = 90 - x[/tex]
This implies that, subtract the known angle from 90 to get the unknown angle.
Assume [tex]x = 40[/tex]
We make use of: [tex]y = 90 - x[/tex]
[tex]y = 90 - 40 = 50[/tex]
(b) Isosceles triangle
The sum of angles in an isosceles triangle is:
[tex]x + y + y = 180[/tex] ---- y appear twice because the base angles are equal
[tex]x + 2y = 180[/tex]
Make x the subject
[tex]x = 180 - 2y[/tex]
Make y the subject
[tex]y = \frac{180 - x}{2}[/tex]
Assume [tex]x = 40[/tex], we make use of:
[tex]y = \frac{180 - x}{2}[/tex]
[tex]y = \frac{180 - 40}{2}[/tex]
[tex]y = \frac{140}{2}[/tex]
[tex]y = 70[/tex]
Assume [tex]y = 70[/tex], we make use of:
[tex]x = 180 - 2y[/tex]
[tex]x = 180 - 2 * 70[/tex]
[tex]x = 180 - 140[/tex]
[tex]x = 40[/tex]
