The triangle that forms is a right-angled triangle. To work out the area, you just do the base × height, all divided by 2.
Therefore, you do 5 (the base) × 4 (the height) and you get 20.
Then you divide by 2 to finish the equation and you should find that the total area of the triangle is 10 units² (20 ÷ 2 = 10).
Hope that helps :)
If the 10 books are all different, we have:
• 10 ways of selecting the first book,
,• 9 ways of selecting the second book,
,• 8 ways of selecting the third book,
,• 7 ways of selecting the fourth book.
The total number of ways to arrange 4 of the 10 books is:
Answer
There are 5040 ways of arranging the books.
Full working out shown from step 1 to last.
follow it and you get 24 square feet as final answer. Good luck in other questions!!!
