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Parallelogram ABCD with m < B = 5x and m < C = 3x+4. How do I find the number of degree in < D?
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There is nothing easier.
The angles B and C are consecutive angles of the parallelogram.
Consecutive angles of any parallelogram are supplementary. It means that they sum up to 180 degrees.
It gives you an equation
5x + (3x+4) = 180.
5x + 3x + 4 = 180
8x = 180-4 = 176 ====> x = = 22.
Therefore, angle B is 5*22 = 110.
In parallelogram ABCD, the angles B and D are opposite angles.
In any parallelogram, the opposite angles are congruent.
Therefore, the measure of the angle D is the same as for angle B, i.e. 110 degrees.
Solved.
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To see other similar solved problems, look into the lessons
- Solved problems on supplementary and complementary angles
- Solved problems on angles of a triangle
- Solved problems on angles of a parallelogram (*)
- Solved problems on angles of a quadrilateral
- Solved problems on angles of a polygon
- Solved problems on missed angle of a polygon
- Solved problems on angles of a regular polygon
in this site.
The most relevant lesson is marked (*) in this list.
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GEOMETRY - YOUR ONLINE TEXTBOOK
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The referred lessons are the part of this online textbook under the topic "Finding angles of triangles, parallelograms and rectangles".
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