Question

Help (this for a friend) a 62.1 b 117.4 c 122.1 d 164.5

Answer 1

Answer:

c. 122.1 cm

Step-by-step explanation:

so l * w + $\frac{\pi r^2}{2}$

since 6 cm is the diameter

6/2 = 3

the radius (or r) is 3

so 18 * 6 + $\frac{3.14 * 3*3}{y}$

108 + $\frac{3.14*9}{y}$

108 + $\frac{28.26}{2}$

108 + 14.13 = 122.13

simplified: 122.1 cm

hope this helps:)

Answer 2

Answer:

C. 122.1

Step-by-step explanation:

The area of a semicircle is HALF of the area of the circle. As the area of a circle is $\pi r^2$. So, the area of a semicircle is $\frac{1}{2}(\pi r^2)$, where r is the radius.

18 × 6

= 108

108 $cm^2$ is the area of the rectangle,

For the semicircle, we know the diameter is equal to 6 cm,

(Remember that Diameter is equal to the radius times 2 (r × 2)),

To find the radius, divide the diameter by 2,

6 ÷ 2

= 3

The radius of the semicircle is 3 cm

Now use the equation $\frac{1}{2}(\pi r^2)$ to find the area of the semicircle,

$\frac{1}{2} (\pi 3^2)$

(Remember pie is 3.14...)

Slove:

$\mathrm{Remove\:parentheses}:\quad \left(a\right)=a$

$=\frac{1}{2}\pi 3^2$

$\mathrm{Multiply\:fractions}:\quad \:a\cdot \frac{b}{c}=\frac{a\:\cdot \:b}{c}$

$=\frac{1\pi 3^2}{2}$

$\mathrm{Multiply:}\:1\pi =\pi$

$=\frac{3^2\pi }{2}$

$3^2=9$

$=\frac{9\pi }{2}$

$\frac{9\pi }{2} =\left(\mathrm{Decimal:\quad }\:14.13716\dots \right)$

Now take the decimal 14.13716.... and round to the nearest tenth,

14.13

(Remember 4 or less keep it the same, 5 or more bring the value up one more)

3 less than 5 so keep the 1 the same,

14.1

Now add 108 and 14.1,

108 + 14.1

= 122.1

Therefore the total area of the shape is 122.1 $cm^2$. Answer ⇒ C.