Answer:
Step-by-step explanation:
The rock will hit the surface when its height equals zero.
t^2-8t-10=0
t^2-8t=10
t^2-8t+16=10+16
(t-4)^2=26
t-4=+(26^(1/2))
t=4+(26^(1/2))
t=9.1s
Answer:
284cm^2
Step-by-step explanation:
first, we split up the shape into seperate sections that we can easily find the areas of.
i will draw vertical lines in the bottom left and right, leaving me with 2 seperate rectangles and 1 irregular pentagon.
we know that these rectangles are 4x8cm, so we do 4 * 8 which gives us 32.
there are 2 of these, so 32 x 2 = 64cm^2.
now, i chose to seperarte the pentagon into a rectangle and a triangle,
and i found the height and width of the rectangle to be (18 - (4+4)) x (8+7), or 10 x 15.
the area of the rectangle is 150cm^2.
now, for the triangle.
the line through the centre of th shape is 22cm long, but we only want the part in the triangle. luckily, there are mesurements that can help us with this.
8 + 7 = 15.
22 - 15 = 7.
now we know that the height of the triangle is 7 cm.
from earlier, we also know the base, which is 10cm.
7 x 10 = 70cm^2.
now we add all these together:
70 + 150 + 64 = 284cm^2
When squaring a number, you multiply the number by itself. Ex- 4squared would be 16. 4 x 4 = 16. Ex- 8squared would be 64.
8 x 8 = 64
Since the distance from the two known coordinates are known, you can find the slope of the line (for lack of a better word) to work backwards. there is a +5 unit gap between -21 and -16, so the next number would be -26. So, without havint to do any more work, the answer is B.
