PLEASE HELP NOT MUCH TIME LEFT

I need help answering the question in the picture provided

adoni [48]

answer:

(a).

Equation of circle is x² + y² - 25 = 0

(b).

(-5, 0) » yes

(√7, 1) » no

(-3, √21) » no

(0, 7) » no

Step-by-step explanation:

(a).

If centred at origin, centre is (0, 0)

General equation of circle:

${ \boxed{ \bf{ {x}^{2} + {y}^{2} + 2gx + 2fy + c = 0}}}$

but g and f are 0:

${x}^{2} + {y}^{2} + c = 0 \\ but : \\ c = {g}^{2} + {f}^{2} - {r}^{2} \\ c = { - 25}$

8 0

3 years ago

What is the perimeter P of △DEF to the nearest whole number?

schepotkina [342]

Answer:

perimeter of ΔDEF ≈ 32

Step-by-step explanation:

To find the perimeter of the triangle, we will follow the steps below:

First, we will find the length of the side of the triangle DE and FF

To find the length DE, we will use the sine rule

angle E = 49 degrees

e= DF = 10

angle F = 42 degrees

f= DE =?

we can now insert the values into the formula

=

cross-multiply

f sin 49° = 10 sin 42°

Divide both-side by sin 49°

f = 10 sin 42° / sin 49°

f≈8.866

which implies DE ≈8.866

We will now proceed to find side EF

To do that we need to find angle D

angle D + angle E + angle F = 180° (sum of interior angle)

angle D + 49° + 42° = 180°

angle D + 91° = 180°

angle D= 180° - 91°

angle D = 89°

Using the sine rule to find the side EF

angle E = 49 degrees

e= DF = 10

ange D = 89 degrees

d= EF = ?

we can now proceed to insert the values into the formula

=

cross-multiply

d sin 49° = 10 sin 89°

divide both-side of the equation by sin 49°

d= 10 sin 89°/sin 49°

d≈13.248

This implies that length EF = 13.248

perimeter of ΔDEF = length DE + length EF + length DF

=13.248 + 8.866 + 10

=32.144

≈ 32 to the nearest whole number

perimeter of ΔDEF ≈ 32

6 0

3 years ago

What is the lateral surface area of a cube with side length of 9 cm

Wittaler [7]

S^2 = one face of a cube
S^2 × 6 = entire Surface Area (SA) of cube
One face = 9^2 = 81 cm^2
SA = 81 × 6 = 486 cm^2

3 0

3 years ago

Consider parallelogram ABCD. Which of the following transformations will change the perimeter of the parallelogram?

jeka57 [31]

In geometry, transformation involves changing the position and/or size of a shape.

The transformation that will change the size of ABCD is dilation.

There are four transformations in geometry:

Translation
Reflection
Rotation
Dilation

Of all types of transformation, dilation will change the size of the shape,

The new shape will either be enlarged or reduced

Either ways, the size of the shape will be altered.

When the size is altered, the perimeter will not remain the same.

Hence. dilation will change the perimeter of ABCD.