Answer:
a>4 or a < 8
Step-by-step explanation:
We can start with the inequality on the left
-a + 2(4+3a) > 28
expand using the distributive property
-a + 8 + 6a > 28
5a + 8 > 28
subtract 8 from both sides to isolate the variable and its coefficient
5a > 20
divide both sides by 5 to isolate a
a > 4
moving on to the inequality on the right
2a - (3a+4) > -12
treat the minus sign as a -1
2a + (-1)(3a+4) > - 12
expand
2a - 3a - 4 > - 12
-a - 4 > -12
add 4 to both sides to isolate a and its coefficient
-a > - 8
multiply both sides by -1 but change the sign because we are multiplying by a negative number
a < 8
Answer:
The radius of the circle P = 2√10 = 6.325
Step-by-step explanation:
∵ AB is a tangent to circle P at A
∴ (AB)² = BC × BE
∵ BC = 8 , AB = 12 , ED = 6
∵ BE = ED + DC + CB
∴ BE = 6 + CD + 8 = 14 + CD
∴ (12)² = 8 × (14 + DC) ⇒ (12)²/8 = 14 + CD ⇒ CD = (12)²/8 - 14
∴ CD = 4
Join PC and PE (radii)
In ΔBDC and ΔPDE ⇒ ∵ ∠PDC = Ф , ∴ ∠PDE = 180 - Ф
Use cos Rule:
∵ r² = (PD)² + (DC)² - 2(PD)(DC)cosФ
∴ r² = 16 + 16 - 32cosФ = 32 - 32cosФ ⇒ (1)
∵ r² = (PD)² + (DE)² - 2(PD)(DE)cos(180 - Ф) ⇒ cos(180 - Ф) = -cosФ
∴ r² = 16 + 36 + 48cosФ = 52 + 48cosФ ⇒ (2)
∵ (1) = (2)
∴ 32 - 32 cosФ = 52 + 48cosФ
∴ 32 - 52 = 48cosФ + 32cosФ
∴ -20 = 80cosФ
∴ cosФ = -20/80 = -1/4
∴ r² = 32 - 32(-1/4) = 32 + 8 = 40
∴ r = √40 = 2√10 = 6.325
I believe 2 dollars and 50 cents
Answer:
35cm
Step-by-step explanation:
The net of a regular pentagon has 10 sides.
Since each of the faces are equilateral triangles, the side lengths are equal.
Therefore:
Length of each side of the net = 70/10 =7cm
Therefore, the base is a regular pentagon of side length 7cm.
The perimeter of the base of the pyramid = 5 X 7
=35cm
The perimeter of the base of the pyramid is 35cm.
Answer:
4
Step-by-step explanation:
4 - 2 = 4 + -2 = -2 + 4
