Answer 96in2
Step-by-step explanation:
formula to find area = base x height
substitute the values
= 10 x 9
= 90 cm2
Answer:11
Step-by-step explanation:
Boys : girls=7:1
Sum of ratio=7+1=8
Let them number of girls be y
Then they number of boys=y+66
Total number of pupils=y+y+66
Total number of pupils=2y+66
Number of girls=(girls ratio)/(sum of ratio) x (total number of pupils)
y=1/8 x (2y+66)
Cross multiply
y x 8=2y + 66
8y=2y + 66
Collect like terms
8y-2y=66
6y=66
Divide both sides by 6
6y/6=66/6
y=11
The number of girls is 11
Answer:
first one
Step-by-step explanation:
Answer:
Heavenly, we need the forumula for the area of a triangle, do you know it?
Step-by-step explanation:
Area of a triangle is (1/2 ) * B*H
where B = base
H = height
then
A = 1/2* B * H
A is given to be 20
B = b
H = b+4
plug all those into the formula,
20 = (1/2)*b*(b+4)
use your algebra skillz :P
20 = 1/2 *( 
+ 4b)
20*2 = + 4b
40 = + 4b
0 = + 4b-40
rewrite the above so it's in x format
+ 4x -40 = 0
use the quadratic formula to find x , and for our problem, remember that x represents the base, or b, but don't mix it up with the b in the quadatic fomula, with the b of the triangle, which is the base, they are differnt "b"s :P
X = (b±
) / 2*a
a = 1
b = 4
c = -40
x = (4±
) /2*1
x = ( 4±
) / 2
x = (4±
) / 2
x = (4±13.266499)/2
x= 2±6.633249
x = 2 + 6.633249 = 8.633
b= 8.633 cm
Extraneous solutions, is answers that we get because of squaring both sides of the radical equation, but in reality, they are not going to be the solutions of the given equation.
(√(4x+41))²=(x+5)²
4x+41=x²+10x+25
x²+6x-16=0
(x-2)(x+8)=0
x1=2 , x2=-8,
And now we must to check them by substitution into initial equation
√(4x+41)=x+5
1) x=2, √(4*2+41)=2+5, √49=7, 7=7 true
2) x=-8, √(4*(-8)+41)=-8+5, √9 =-3 false,
so an extraneous solution x=-8
