Since if he gets the driveway done in 20 minutes he gets 1/20th of the driveway done in 1 minute (if x=20 then x/20=1 by dividing both sides by 20) and if his brother gets 1/12th of the driveway done in one minute, then if t represents the time it takes to shovel the driveway, t/20+t/12=1 driveway shoveled as 1/20+1/12=amount they can do in 1 minute, so t/20+t/12 is how much they can do in t minutes. Multiplying both sides by 20*12=240, we get 12t+20t=32t=240. Dividing both sides by 32, we get 240/32=7.5 minutes to shovel the driveway.
The reflection of BC over I is shown below.
<h3>
What is reflection?</h3>
- A reflection is a mapping from a Euclidean space to itself that is an isometry with a hyperplane as a set of fixed points; this set is known as the reflection's axis (in dimension 2) or plane (in dimension 3).
- A figure's mirror image in the axis or plane of reflection is its image by reflection.
See the attached figure for a better explanation:
1. By the unique line postulate, you can draw only one line segment: BC
- Since only one line can be drawn between two distinct points.
2. Using the definition of reflection, reflect BC over l.
- To find the line segment which reflects BC over l, we will use the definition of reflection.
3. By the definition of reflection, C is the image of itself and A is the image of B.
- Definition of reflection says the figure about a line is transformed to form the mirror image.
- Now, the CD is the perpendicular bisector of AB so A and B are equidistant from D forming a mirror image of each other.
4. Since reflections preserve length, AC = BC
- In Reflection the figure is transformed to form a mirror image.
- Hence the length will be preserved in case of reflection.
Therefore, the reflection of BC over I is shown.
Know more about reflection here:
brainly.com/question/1908648
#SPJ4
The question you are looking for is here:
C is a point on the perpendicular bisector, l, of AB. Prove: AC = BC Use the drop-down menus to complete the proof. By the unique line postulate, you can draw only one segment, Using the definition of, reflect BC over l. By the definition of reflection, C is the image of itself and is the image of B. Since reflections preserve , AC = BC.
Million, Billion, Trillion, and Quadrillion
Answer:
6 cm
Step-by-step explanation:
Volume of a Prism = base area x height =
Base area = length x width = 12 x 2 = 24 cm^2
Volume = 24 x 3 = 72 cm^3
Volume of a pyramid = 1/3( l x w x h)
72 = 1/3( 6x6 x h)
Multiply both sides of the equation by 3
216 = 36 x h
divide both sides by 36
h = 6