In the diagram above,
A B is parallel to E H , and B D is parallel to F H .
Also, A B = B C and E F = F H .
If ∠ E G C = 7 0 ∘ , then ∠ D = ?
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
Thank you.
DEGC isn't a rectangle.
∠ E G C = 7 0 ° , so ( A B and E H are parallel) ∠ C A B = 7 0 ° .
A B = B C , so ∠ A C B = 7 0 ° = ∠ D C G
If M is the midpoint of B D and E H (because they can't be parallel), then ∠ C M G = 1 8 0 ° − 2 ∗ 7 0 ° = 4 0 ° . Since B D and F H are parallel, ∠ E H F = 4 0 ° . So ∠ C D E = 3 6 0 ° − ∠ D C G − ∠ C G E − ∠ G E D = 3 6 0 ° − 7 0 ° − 7 0 ° − 1 4 0 ° = 8 0 °
Thank you.
Problem Loading...
Note Loading...
Set Loading...
∠ E G C = 7 0 ∘ ⟹ ∠ C A B = 7 0 ∘ because A B and E H are parallel.
A B = B C ⟹ ∠ A C B = 7 0 ∘ as well, and therefore also ∠ D C G = 7 0 ∘
Let ∠ C D F = x . Then because B D is parallel to F H the ∠ E F H = 1 8 0 ∘ − x .
∠ F E H = 2 1 ( 1 8 0 − ∠ E F H ) = 2 x
∠ D E G = 1 8 0 ∘ − ∠ E F H = 1 8 0 ∘ − 2 x
The sum of the angles in rectangle D E G C is
3 6 0 ∘ = x + 7 0 ∘ + 7 0 ∘ + 1 8 0 ∘ − 2 x
From that x = 8 0 ∘