Find the circumference and the area of a circle with radius 4 cm Please help!

Mathematics

2 answers:

Alexus [3.1K]2 years ago

5 0

Circumference: 2 * pi * r
pi = 3.14, r = 4
2 * 3.14 * 4 = 25.12
Circumference: 25.12 cm

Area = pi * r^2
pi = 3.14, r = 4
3.14 * 4^2 = 50.24
Area: 50.24 cm^2

Akimi4 [234]2 years ago

3 0

Answer:

Circumference: 8πcm

Area: 16πcm²

Step-by-step explanation:

Circumference:

To find the circumference of a circle, use the formula c = 2πr, where r is the radius. Use 3.14 for pi.

r = 4

c = 2πr

c = 2(3.14)r

c = 2(3.14)4

c = 25.12cm

Area: To find the area of a circle, use the formula πr², where r is the radius. Use 3.14 for pi.

r = 4

a = πr²

a = (3.14)r²

a = (3.14)4²

a = (3.14)16cm²

a = 50.24 cm²

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Kipish [7]

Answer:

$y=-\frac{4}{7} x+\frac{55}{7}$

Step-by-step explanation:

Change the given equation to slope-intercept to get $y=\frac{7}{4}x-\frac{1}{4}$ . When you multiply the slopes of perpendicular lines, you get -1. -1 divided by $\frac{7}{4}$ is $-\frac{4}{7}$ . The slope of the new line is then $-\frac{4}{7}$ . The perpendicular line passes through (5, 5) so you can have the equation $5=-\frac{4}{7} (5)+b$ . Simplifying gets $b = \frac{55}{7}$ . So now the final equation for the perpendicular line is $y=-\frac{4}{7} x+\frac{55}{7}$