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GEOMETRY:

I might just be slow but I don't understand what this question is asking at all. Can someone help?

GEOMETRY: I might just be slow but I don't understand what this question is asking-example-1
User Nimmy
by
7.5k points

1 Answer

7 votes

Answer:


b = 90


d = 100


c = 80

Explanation:

The problem is asking for the values of the variables
b,
c, and
d in the given parallelogram with angles
d\textdegree,
c\textdegree,
(b-10)\textdegree, and
(b+10)\textdegree.

To solve for these variables, we can construct three equations using the knowledge that any two adjacent angles of a parallelogram are supplementary (their measures add to 180º).

The first equation shows that the top two angles are supplementary:


d\textdegree + c\textdegree = 180\textdegree

The second equation shows that the bottom two angles are supplementary:


(b-10)\textdegree + (b+10)\textdegree = 180\textdegree

The third equations shows that the left two angles are supplementary:


d\textdegree + (b-10)\textdegree = 180\textdegree

First, we can solve for
b in the second equation using simple algebraic manipulation.


(b-10)\textdegree + (b+10)\textdegree = 180\textdegree


(b+b)\textdegree + (10-10)\textdegree = 180\textdegree


2b\textdegree = 180\textdegree


b\textdegree = 90\textdegree


b = 90

Using this
b-value, we can solve for
d by rewriting the third equation, plugging
90 in for
b:


d\textdegree + (b-10)\textdegree = 180\textdegree


d\textdegree + (90-10)\textdegree = 180\textdegree


d\textdegree + 80\textdegree = 180\textdegree


d\textdegree = 100\textdegree


d = 100

Finally, we can solve for
c in the first equation by plugging
100 in for
d:


d\textdegree + c\textdegree = 180\textdegree


100\textdegree + c\textdegree = 180\textdegree


c\textdegree = 80\textdegree


c = 80

User Spajus
by
8.0k points