I need help please. daad

PLEASE HELP!

IrinaVladis [17]

Answer:

Step-by-step explanation:

<h3>Sphere:</h3>

1) a) r = 7 cm

$\sf \boxed{\text{Volume of sphere=$\dfrac{4}{3}\pi r^3$}}$

$\sf =\dfrac{4}{3}*3.14*7*7*7\\\\= 1436 \ cm^3$

$\sf \boxed{\text{\bf Surface area of sphere = $4\pi r^2$}}$

= 4*3.14 * 7 * 7

= 615.44 cm²

b) r= 8.4 cm

$Volume = \dfrac{4}{3}\pi r^3$

$\sf =\dfrac{4}{3}*\dfrac{22}{7}*8.4*8.4*8.4\\\\= 2483.7 \ cm^3$

Surface area = 4*3.14*8.4*8.4

= 887.04 cm²

<h3>Hemisphere:</h3>

a) r = 6 cm

$\sf \boxed{\text{\bf Volume of hemisphere =$\dfrac{2}{3} \pi r^3$}}$

$\sf =\dfrac{2}{3}*3.14*6*6*6\\\\= 452.16 \ cm^3$

$\sf \boxed{\text{\bf Surface area of hemisphere=3 \pi r^2}}$ $\sf \boxed{\text{\bf Surface area of hemisphere = $3 \pi r^2$}}$

= 3 * 3.14 * 6 * 6

= 339.12 cm²

3 0

2 years ago

A car travels 60km in 30 minutes. In how much time will it cover 100 km?

Daniel [21]

Answer:

About 40 Minutes, Or something close to that

Step-by-step explanation:

The car covers 60 km in 90 minutes or its speed = 60 km*60/90 min = 40 km/hr . So to cover 100 km at the same speed it will take 100/40 = 40 Min

5 0

3 years ago

Read 2 more answers

Geometry help. Inscribing circle help and constructing lines.

prohojiy [21]

<h3>1. Inscribe a circle ΔJKL. Identify the point of concurrency that is the center of the circle you drew. </h3>

To inscribe a circle in the attached triangle, we must follow the following steps. The resultant figure is the first one below.

1. Draw the angle bisector of angle JKL. The straight line in the green one.

2. Draw the angle bisector of angle KLJ. The straight line in the blue one.

3. Draw point D at these two lines.

4. Draw a line through point D perpendicular to side JK. The straight line in the red one.

5. Mark point G at the red line and side JK.

6. Draw a circle with center at D (point of concurrency) and a radius of DG.

<h3>2. Circumscribe a circle ΔFGH. Identify the point of concurrency that is the center of the circle you drew. </h3>

To circumscribe a circle in the attached triangle, we must follow the following steps:

1. Draw the perpendicular bisector of the side FG. The straight line in the red one. The resultant figure is the second one below.

2. Draw the perpendicular bisector of the side GH. The straight line in the blue one.

3. The center of the circle is the intersection of these two lines

4. Draw a circle with center at D (point of concurrency).

<h3>3. Construct the two lines tangents to circle</h3>

A tangent to a circle is a straight line that touches the circle at an only point. If a point A is outside a circle, we can draw two lines that pass through this point and are tangent to the circle at two different points each. So this is shown in the third figure. Lines red and blue are tangent to the circle at two different points.