11.
(87+91+86+x)/4=90.
x=96.
13.
50×y > 130.
the lowest number could be 3, because 50×2=120, which is less than 130.
I think the answer is 84/3
9514 1404 393
Answer:
(x +6)^2 +(y -10)^2 = 225
Step-by-step explanation:
The standard form equation for a circle is ...
(x -h)^2 + (y -k)^2 = r^2
where the center is (h, k) and the radius is r.
The center of a circle is the midpoint of any diameter. The midpoint between two points is the average of their coordinates.
((-15, -2) +(3, 22))/2 = (-15+3, -2+22)/2 = (-6, 10)
The radius can be found using the distance formula, or by simply putting one of the given points in the equation for the circle to see what the constant (r^2) needs to be.
(x -(-6))^2 +(y -10)^2 = (-15-(-6))^2 +(-2-10)^2
(x +6)^2 +(y -10)^2 = 81 +144 = 225
The equation of the circle is ...
(x +6)^2 +(y -10)^2 = 225
Answer:
C
Step-by-step explanation:
To make it easy let's start by organizing our information :
- AC=12 AND BD=8
- ABCD is a rhombus
- K and L are the midpoints of sides AD and CD
- we notice that the rhombus ABCD is divided into four right triangles
What do you think of when you hear a right triangle ?
- The pythagorian theorem !
AC and BD are khown so let's focus on them .
If we concentrated we can notice that AB and BD are cossing each other in the midpoints . why ?
Simply because they are the diagonals of a rhombus .
ow let's apply the pythagorian theorem :
- (AC/2)² + (BD/2)² = BC²
- 6²+4²=52
- BC²= 52⇒
=BC
Now we khow that : AB=BC=CD=AD=
This isn't enough . Let's try to figure out a way to calculate the length of KL wich is the base of the triangle
- KL is parallel to AC
- k is the midpoint of AD and L of DC
I smell something . yes! Thales theorem
- KL/AC=DL/DC=DK/AD WE4LL TAKE OLY ONE
- KL/12=
/2*
- KL/12=1/2⇒ KL=6
Now we have the length of the base kl
Now the big boss the height :
- notice that you khow the length of KL
- BD crosses kl from its midpoint and DL =
/2
What I want to do is to apply the pythgorian thaorem to khow the lenght of that small part that is not a part of the height of the triangle . I will call it D
- DL²=(KL/2)²+D²
- 52/4= 9+ D²
- D² = 52/4-9 +4 SO D=2
now the height of the trigle is H= BD-D= 8-2=6
NOw the area of the triangle is :
- A=(KL*H)/2 ⇒ A= (6*6)/2=18
THE ANSWER IS 18 SQ.UN