Do you know how many friends he has then you can answer the question
<u>Let's consider the facts at hand</u>:
- By Vertical Angle Theorem ⇒ ∠BCE = ∠DCF
- ∠BEC = ∠DFC
- Sides BE = DF
<u>Based on the diagram, triangles BCE and triangles DCF are similar</u>
⇒ based on the Angle-Angle theorem
⇒ since ∠BCE = ∠DCF and ∠BEC = ∠DFC
⇒ the two triangles are similar
Hope that helps!
<em>Definitions of Theorem I used:</em>
- <u><em>Vertical Angle Theorem: </em></u><em>opposite angles of two intersecting lines must be equal</em>
- <u><em>Angle-Angle Theorem:</em></u><em> if two angles of both triangles are equal, then the given triangles must be similar</em>
<em />
Let red marbles be x.
Blue : 2x
Red : x
Yellow : x+8
2x + x + x + 8 = 56
4x = 48
x = 12
Red marbles: 12
Blue : 24
Yellow: 20
Vector

.

. So the sum is

.
For the second, the magnitude is the square root of the sum of the squares of the components. This is equal to

.