All categories

2 years ago

Given the center and radius of a circle, write the equation of the circle.

Mathematics

1 answer:

Mashutka [201]2 years ago

5 0

Answer:

(x + 2)² + (y - 1)² = 25

General Formulas and Concepts:

Algebra I

Coordinates (x, y)

Pre-Calc

Circle Center Formula: (x - h)² + (y - k)² = r²

(h, k) is center
r is radius

Step-by-step explanation:

Step 1: Define

Identify variables

(h, k) = (-2, 1)

r = 5

Step 2: Find Equation

Substitute in variables [Circle Center Formula]: (x - -2)² + (y - 1)² = 5²
Simplify: (x + 2)² + (y - 1)² = 25

Topic: Pre-Calculus

Unit: Conics

Book: Pre-Calculus (McGraw Hill)

You might be interested in

Why is using coins as money easier than using gold bars?

Solnce55 [7]

Answer:

because coins are more portable

Step-by-step explanation:

5 0

2 years ago

The 5th term in a geometric sequence is 160. The 7th term is 40. What are possible values of the 6th term of the sequence?

omeli [17]

Answer:

C. The 6th term is positive/negative 80

Step-by-step explanation:

Given

Geometric Progression

$T_5 = 160$

$T_7 = 40$

Required

$T_6$

To get the 6th term of the progression, first we need to solve for the first term and the common ratio of the progression;

To solve the common ratio;

Divide the 7th term by the 5th term; This gives

$\frac{T_7}{T_5} = \frac{40}{160}$

Divide the numerator and the denominator of the fraction by 40

$\frac{T_7}{T_5} = \frac{1}{4}$ ----- equation 1

Recall that the formula of a GP is

$T_n = a r^{n-1}$

Where n is the nth term

So,

$T_7 = a r^{6}$

$T_5 = a r^{4}$

Substitute the above expression in equation 1

$\frac{T_7}{T_5} = \frac{1}{4}$ becomes

$\frac{ar^6}{ar^4} = \frac{1}{4}$

$r^2 = \frac{1}{4}$

Square root both sides

$r = \sqrt{\frac{1}{4}}$

r = ± $\frac{1}{2}$

Next, is to solve for the first term;

Using $T_5 = a r^{4}$

By substituting 160 for T5 and ± $\frac{1}{2}$ for r;

We get

$160 = a \frac{1}{2}^{4}$

$160 = a \frac{1}{16}$

Multiply through by 16

$16 * 160 = a \frac{1}{16} * 16$

$16 * 160 = a$

$2560 = a$

Now, we can easily solve for the 6th term

Recall that the formula of a GP is

$T_n = a r^{n-1}$

Here, n = 6;

$T_6 = a r^{6-1}$

$T_6 = a r^5$

$T_6 = 2560 r^5$

r = ± $\frac{1}{2}$

So,

$T_6 = 2560( \frac{1}{2}^5)$ or $T_6 = 2560( \frac{-1}{2}^5)$

$T_6 = 2560( \frac{1}{32})$ or $T_6 = 2560( \frac{-1}{32})$

$T_6 = 80$ or $T_6 = -80$

$T_6 =$ ±80

Hence, the 6th term is positive/negative 80

8 0

2 years ago

11.68 - 0.48 ÷ (-1.6) = need help I need a way to solve this problem

ExtremeBDS [4]

Step-by-step explanation:

11.68-0.48

= 11.20

11.20÷1.6

= 7.0 or 7

ahh this is the correct answer.

so if it helps don't forget to like and Mark me.

4 0

3 years ago

Read 2 more answers

How much did it cost summer to to buy 2.6 pounds of granola at the old price

coldgirl [10]

It was $6.00 per pound. So 2 pounds would be $12. But there is still that .6 of a pound left. If we know 1 pound costs $6, then we know 1/10th of a pound will cost $0.60. So 6 x .60 = 3.60. Add 12 and 3.60, and you get 15.60 for 2.6 pounds of granola at the old price.

6 0

3 years ago

Read 2 more answers

Yolanda purchased a prepaid phone card for $25 . long distance calls cost 17 cents a minute using this card. yolanda used her ca

USPshnik [31]

So $25 - $17.35 = $7.65

7.65÷ 17 = 45
45 = 45 min

4 0

3 years ago