what grade is this and what are the answers i need them to help
Answer: 784π mm²
Step-by-step explanation: To find the area of a circle, start with the formula for the area of a circle which is shown below.
Area = πr²
Notice that here, we're given the diameter instead of the radius.
Remember that the radius is equal to half of the diameter. So the radius of this circle will be equal to half 56 millimeters or 28 millimeters.
So plugging into the formula, we have (π)(28 mm)².
A common mistake is to plug 56 millimeters into the formula but remember that we must plug in the radius and not the diameter.
Multiplying, (28 mm)² is equal to (28 mm)(28 mm) or 784 mm².
So we have 784π mm².
So the area of the circle is 784π mm².
Answer:
The solution is (-5, -2).
Step-by-step explanation:
We'll use "elimination by addition and subtraction."
Multiply the second row by -2. Our system
– 7x – 10y = 45
-3x - 5y = 25
becomes:
– 7x – 10y = 45
+6x + 10 y = -50
-------------------------
-x = 5, so that x = -5.
Substituting -5 for x in the second equation results in
-3(-5) - 5y = 25, or 15 - 5y = 25. This reduces to
-5y = 10, so that y must be -2.
The solution is (-5, -2).
y=-2x
We know this because the slope is -2 (slope is found using rise/run, in this case the rise is 2 and the run is -1, so 2/-1=-2), and the y-intercept is at 0 (the y-intercept is the point at which a line crosses the y-axis).
:)
