A circle has a radius of 2 find the exact area of the circular region

Mathematics

2 answers:

Nesterboy [21]3 years ago

7 0

The answer is approximately 12.57

34kurt3 years ago

3 0

It has an area of 12.57

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Work out area of this semi circle with diameter 10

ANTONII [103]

Area of a circle is pi x r^2

R is the radius which is have the diameter: r = 10/2 = 5

Area of the full circle would be 3.14 x 5^2 = 3.14 x 25 = 78.5 square units.

A semi circle is half a full circle

Area of the semi circle = 78.5/2 = 39.25 square units.

8 0

3 years ago

HELP PLEASE <br><br>i dont understand at all...

bija089 [108]

An exponent signifies repeated multiplication.

$x\cdot x\cdot x=x^{3}$ the factor x is repeated 3 times

Exponents can be added and subtracted to express the effects of multiplication and division.

$\dfrac{x\cdot x\cdot x\cdot x\cdot x}{x\cdot x\cdot x}=\dfrac{x^{5}}{x^{3}}\\\\=\dfrac{x\cdot x\cdot x}{x\cdot x\cdot x}\cdot x\cdot x=x\cdot x\\\\=x^{(5-3)}=x^{2}$

The addition and subtraction of exponents works the same even when there are more denominator factors than numerator factors.

$\dfrac{x\cdot x\cdot x}{x\cdot x\cdot x\cdot x\cdot x}=\dfrac{x^{3}}{x^{5}}=\dfrac{1}{x^{2}}\\\\=x^{(3-5)}=x^{-2}$

That is, a negative numerator exponent is the same as a positive denominator exponent and vice versa. You can move a factor with an exponent from denominator to numerator and change the sign of the exponent, and vice versa.

Your expression has 3 in the denominator with a negative exponent. It can be moved to the numerator and the exponent changed to positive:

$\dfrac{1}{3^{-2}}=3^{2}\\\\=3\cdot 3=\bf{9}$