By definition, two angles are supplementary if the sum of them is 180 degrees. In this case (see figure attached with the answer) the line AD is transversal to lines AB and DC. This is a proof of the Same-side interior angle theorem.
This theorem states that if we have two lines that are parallel and we intercept those two lines with a line that is transversal to both, same-side interior angles are formed, and also sum 180º, in other words, they are supplementary angles.
Then:
By the definition of a parallelogram, AB∥DC. AD is a transversal between these sides, so ∠A and ∠D are <em><u>same-side interior angles</u></em>. Because AB and DC are <em><u>parallel</u></em>, the same-side interior angles must be <em><u>supplementary</u></em> by the same-side interior angles theorem. Therefore, ∠A and ∠D are supplementary.
Answer:9.4cm2
Step-by-step explanation:
Answer:
Part A) The area of the figure is 
Part B) The perimeter of the figure is 
Step-by-step explanation:
step 1
Find the area of the figure
we know that
The area of the figure is equal to the area of triangle ABD plus the area of triangle BCD
The area of triangle is equal to

<u>Area of triangle ABD</u>
Observing the graph


substitute

<u>Area of triangle BCD</u>
Observing the graph


substitute

The area of the figure is

step 2
Find the perimeter of the figure
we know that
The perimeter of the figure is equal to

we have

the formula to calculate the distance between two points is equal to
Find the distance AB
Find the distance BC
Find the distance CD
Find the distance AD
substitute the values

Answer: The third term is -14
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Explanation:
First term = A(1) = 20, which is given
Second term
A(n) = A(n-1) - 17
A(2) = A(2-1) - 17
A(2) = A(1) - 17 .... note: second term = (first term) - 17
A(2) = 20 - 17
A(2) = 3
Third term
A(n) = A(n-1) - 17
A(3) = A(3-1) - 17
A(3) = A(2) - 17 ... note: third term = (second term) - 17
A(3) = 3 - 17
A(3) = -14