Answer:
SAS theorem
Step-by-step explanation:
If 
and m∠ECD = m∠BCA, then the triangles are similar by the SAS theorem.
So, and m∠ECD = m∠BCA because vertical angles are congruent
Therefore ΔECD is similar to ΔBCA by SAS theorem
Answer:
First figure is regular and convex.
Second figure is irregular and convex.
Step-by-step explanation:
Here given 2 polygons we have to classify these whether these are convex, concave, regular and irregular.
Regular Polygon is the polygon which have all sides and all angles equal.
Convex Polygon is the polygon in which measure of all interior angles less than 180° and if measure of each of interior angle greater than 180° then it is concave.
In the first figure, all sides are equal therefore and each of interior angle of polygon is less than 180°. Hence, the polygon is regular and convex.
In the second figure, all sides are not equal and each of interior angle of polygon is less than 180°. Hence, the polygon is irregular and convex.
In this case, to prove what is required, we must use the Pythagorean theorem to find the diagonal of the square.
If the diagonal of the square is smaller than the diameter of the circle, then the square will fit perfectly in the circle without touching it.
Diagonal = Root ((7 ^ 2) + (7 ^ 2)) = 9.89 cm.
we observed that
9.89cm <11cm.
Therefore we show that:
the square will fit inside the circle without touching the edge of the circle
See picture for explanation.
Here are some, 543,555, 543,123, and 543,369
Hope this helps
