108k views
2 votes
Determine the measure of angle A. PLEASE HELP PLEASE.

a.54 DEGREES
b.1 DEGREES
c.36 DEGREES
d.32 DEGREES

Determine the measure of angle A. PLEASE HELP PLEASE. a.54 DEGREES b.1 DEGREES c.36 DEGREES-example-1
User Petri
by
4.6k points

2 Answers

3 votes

Answer: Choice C) 36 degrees

===================================================

Step-by-step explanation:

Place point B at the intersection of the lines where the 90 degree angle is located.

Place point C at the other intersection point.

So we have triangle ABC.

Since we have a right angle, this means angle B is 90 degrees.

Angle C is 55x-1 degrees because it's vertical to the angle shown. Vertical angles are congruent.

See the diagram below.

-------------

From here we use the idea that all three angles of any triangle always add to 180

A+B+C = 180

(36x) + (90) + (55x-1) = 180

91x+89 = 180

91x = 180-89

91x = 91

x = 91/91

x = 1

Use this x value to find angle A and C

A = 36x = 36*1 = 36

C = 55x-1 = 55*1-1 = 54

Finding angle C is optional since your teacher just wants angle A, but it's useful to help check our answer

A+B+C = 36+90+54 = 180

So this confirms we have the right x value.

Determine the measure of angle A. PLEASE HELP PLEASE. a.54 DEGREES b.1 DEGREES c.36 DEGREES-example-1
User Gouda
by
4.9k points
1 vote

First we find the value of
x. This is quite simple as it's a right angled triangle with one of the angles already given. The main concept is vertically opposite angles meaning if 2 lines intersect, the opposite 2 angles are equal.

So the angle
55x - 1 is for the interior of the triangle too. Now due to angle sum postulate,
36x + 55x -1 + 90 = 180

Simplify this and you get:
91x = 91

Hence,
x = 1

Now, we need to find the value of angle
A which is
36x which is basically
36 * 1 when we replace
x with
1.

Henceforth, angle
A is equal to
36 so option
C is correct. :D

User Christopher Karam
by
4.5k points