The 11th triangular number = 66
Answer:
Step-by-step explanation:
If BD is altitude then AC is the base.
<u>The length of AC is:</u>
- AC =

<u>The length of BD is:</u>
- BD =

<u>The area is:</u>
- A = 1/2bh
- A = 1/2 *
= 18 unit²
Here, (7 * 9) = (7 * 10) - (7 * x)
Here, Take 7 as a common factor according to distributive property:
= 7(10 - x)
Now, 10-x = 9
x = 10-9 = 1
In short, Your Answer would be 1
Hope this helps!
Answer:
It has 5 Faces. The 4 Side Faces are Triangles. The Base is a Square. It has 5 Vertices (corner points)
Step-by-step explanation: