BCDE is a parallelogram. What is the measure of ∠BEC? Enter your answer in the box. ° A parallelogram B C D E. Side E D is the b
ase. The pairs of opposite sides are parallel. Diagonal E C divides the parallelogram into triangles C D E and B C E. Angle B is labeled 60 degrees and angle C E D is labeled 40 degrees.
1 answer:
Solution:
In Parallelogram B CDE
BC= DE, BC ║DE
CD = BE , CD ║BE
Also, ∠B=∠D and ∠C=∠E →→In a parallelogram opposite sides are equal and parallel, as well as opposite angles are equal.Diagonals Bisect each other.
∠B= 60° , ∠C ED= 40°
CE is a transversal and BC║DE.
∠CED=∠BCE = 40° →→Alternate interior angles
In Δ BCE
∠B + ∠BCE + ∠BEC= 180°→→→Angle sum property of Triangle.
60° + 40° + ∠ B E C= 180°
100° + ∠BEC=180°
∠BEC= 180° -100°
∠BEC= 80°
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Answer:
Proved
Step-by-step explanation:
From the given parameters, we have:
i.e. the length of each security numbers
i.e. 2 security numbers
Required
In 513 security numbers, 2 must have matching zeros
To do this, we make use of Pigeonhole principle.
First, we calculate the number of all security numbers not having matching zeros.
Each of the 9 digits can be selected in 2 ways.
2 ways implies that each digit is either 0 or not
So, total selection is:
Apply Pigeonhole principle
The principle states that: suppose there are n items in m containers, where , then there is at least one container that contains more than 1 item.
This means that if there are 512 security number without matching zeros, then there is 1 (i.e. 512 + 1) with matching zeros.