How many ways can you select and arrange 5 books on a shelf out 13 books?
1 answer:
Answer:
There are 154,440 ways.
Step-by-step explanation:
The word arrange means that the order in which the books are placed is important, which means that the permutations formula is used to solve this question.
Permutations formula:
The number of possible permutations of x elements from a set of n elements is given by the following formula:
In this question:
5 books from a set of 13. So
There are 154,440 ways.
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Answer:
Perimeter of the ΔDEF = 10.6 cm
Step-by-step explanation:
The given question is incomplete; here is the complete question with attachment enclosed with the answer.
D, E, and F are the midpoints of the sides AB, BC, and CA respectively. If AB = 8 cm, BC = 7.2 cm and AC = 6 cm, then find the perimeter of ΔDEF.
By the midpoint theorem of the triangle,
Since D, E, F are the midpoints of the sides AB, BC and CA respectively.
Therefore, DF ║ BC and
FD =
= 3.6
Similarly,
FE = 4 cm
And
DE =
= 3 cm
Now perimeter of ΔDEF = DE + EF + FD
= 3 + 4+ 3.6
= 10.6 cm
Perimeter of the ΔDEF is 10.6 cm.
