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+)/2= 10/2 = 5
We have a negative value and a positive one
The altitude is a distance so it can't be negative
H= 5cm
3y = -9x + 12
y = -3x + 4
Is this what you are looking for?
Answer:
x=3
Step-by-step explanation:
10-3x+8x=25
-10 -10
-3x+8x= 15
5x=15
5x/5=15/5
x=3
Step-by-step explanation:
answer: 135 degrees for the missing side
0.2 is the same as 2/10
18/(2/10)
As you may have learned in school, when you divide a fraction, you flip the fraction in the denominator, and change it to multiplication
18/(2/10) becomes 18 x (10/2)
multiply normally
18 x 10 = 180
divide to find answer
180/2 = 90
90 is your answer
hope this helps
Remember, when you meet this problem, flip the second fraction, and change the division sign into multiplication. (always second, never first (if first is a fraction)).
