∠1 and ∠5 are congruent because they are alternate interior angles.
Google image to understand what are alternate interior angles please. the prerequisite is that the two lines are parallel.
255 different groups of 4 paints can be selected out of the 20 paintings.
<h3>How many groups of four paintings can be chosen?</h3>
If we have a set of N elements, the number of groups of different sets of K elements that we can make out of these N is given by:
C(N, K) = N!/(K!*(N - K)!)
In this case we have a total of 20 paintings, and the curator wants to select 4, then we have:
N = 20
K = 4
The number of different combinations of 4 paintings is given by
C(20, 4) = 20!/(4!*16!) = (20*19*18*17)/(4*3*2*1) = 255
This means that 255 different groups of 4 paints can be selected out of the 20 paintings.
If you want to learn more about combinations:
brainly.com/question/11732255
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75 + (75-50) + 100 +100 -50 = 250 m of fencing
50, because 21 + 8 = 39 + 11 = 50
