dolores and four friends went to a buffet dinner.The total cost was at most $130 including the $20 dollar tip they left.How much
2 answers:
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Answer:
5 cm
Step-by-step explanation:
We khow that the altitude of this triangle is 1cm shorter than the base
- Let H be our altitude and B our base and A the area of the triangle
- A= (B*H)/2 ⇒ 15=(B*H)/2
- H is 1cm shorter than B ⇒ B=H+1
- H*(H+1)/2=15 ⇒ H*(H+1)=30⇒ H²+H=30⇒H²+H-30+0
that's a quadratic equation . Let's calculate the dicriminant .
Let Δ be the dicriminant
- a=1
- b=1
- c= -30
- Δ=b²-4*a*c = 1²-4*1*(-30)=1+4*30=121≥0
- Δ≥0⇔ that we have two solutions x and y
- x= (-1-
)/2= (-1-11)/2= -6
- y= (-1+
We have a negative value and a positive one
The altitude is a distance so it can't be negative
H= 5cm
Answer:
10) - 45 degrees
12) 0 degrees
Step-by-step explanation:
10)
Find the x and y components that define the vector that joins C with D:
x-component: -4 - (-8) = - 4 + 8 = 4
y-component: 4 - 8 = -4
use the tangent function to find the angle :
12)
Find the x and y components that define the vector that joins A with B:
x-component: 7 - 4 = 3
y-component: - 1 - (-1) = -1 + 1 = 0
use the tangent function to find the angle :