Focus on triangles DFC and DFE:
- They are both right triangles because DF is perpendicular to EC
- DC=DE
- DF is a common side
So, the two triangles are congruent. It follows that CF=FE, and in particular

And since x=3, the length of EF is

5/9, 9/9, 15/9, 15/9, 24/9. hope this helped.
Answer:
1. C-surface area
2. The formula V = B x h is not suitable, because the surface area of wrapping paper needed to be calculated, not the volume.
V = Ph + 2B = 15x(5+6+9) + 2x 9x3/2 = 327
3. B: Base area
H: Height of solid
4. She said V =220, while V_real = 7x6x4 =168
=> She is wrong
5. Check the Pythagorean theorem 3^2+4^2 =9+16 =25 =5^2
=> Right triangle.
=> Area = 3x4/2 =6
Answer:
-503
Step-by-step explanation:
the statement tell us:
(r - 5)^3 + r^2
r= -3
so we have:
(-3 - 5)^3 + (-3)^2
(-8)^3 + 9
-512+9 = -503