Geometric Equations Including Variables>>>>> The Real Deal, Gongshow Snipes, Zach and Greg

To solve for a variable in a triangle or quadrilateral, you have to know what the sum of the angles. All the sides in a triangle are equal to 180, and in a quadrilateral, they are all equal to 360 degrees. So to solve for x or any variable, you will have to know what all the angles added together are equal to, and you subtract the known numbers from the sum of all the angles.

Examples: One angle in a triangle is 80, another one is 60, and the last angle is unknown. So then the steps you would use to figure out what x is equal to, is to subtract 60 and 80 from 180.

80 + 60 + X = 180
80 + 60 = 140
180 - 140 = 40
X = 40

In a quadrilateral, one side is 70, one is 130, another is 60, and the last side is unknown (y). The steps you would use to solve for y:

70 + 130 + 60 + Y = 360
70 + 130 + 60 = 260
360 - 260 = 100
Y = 100

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If you need extra help or practice, try these practice questions:

1.a) In a triangle, angle A is 80 degrees, and angle C is 40 degrees. Find the measure of angle B.

b) Parallelogram DEFG has 2 sets of parallel lines. D and F are opposite angles, and E and G are opposite angles.
D is 63 degrees. Find the measures for all of the angles.

c) An irregular pentagon's angles add up to 540 degrees. It has 2 right angles, a 73 degrees angle, a 124 degrees angle, and x.
Solve for x.