### Scribe Post for April 28, 2010

Wednesday, April 28, 2010
Hello 9-05! Today in class we were given 3 problems. These problems were hard for some people so I will explain it to you!

1) A bag contains 36 marbles. There are one quarter as many purple marbles as red ones. There are three times as many green as purple marbles. How many green marbles in the bag?

There are 36 marbles in the bag.
so Red + Purple + Green = 36
We don't know how many red marbles there are so red will be x. There is 1/4 purple marbles out of the red ones so purple will be 1/4x. And lastly, for green, there are 3 times the number of purple marbles so green will represent 3(1/4x).

So you have to add all of those to get the number of marble in the bag.
x + 1/4x + 3(1/4x) = 36
That is your equation. Now solve for x.

So there are 18 red marbles. Now you fill in x will 18 to find out how many green marbles there are in the bag.

3(1/4x) = Number of green marbles
3(18/4) = Green
3(4.5) = Green
13.5 = green

There are 13.5 green marbles in the bag.

2) A skier takes 1.2 minutes to complete a run of 2 km. How fast in meters/second was he going?

First you must convert minutes into seconds and kilometers into meters. There are 60 sec in 1 min and there are 1000 meters in 1 km.

1.2(60)=72 sec
2(1000)=2000 m

Then you use to formula s=d/t.

He was going at a speed of 27.78 m/s.

3) A regular hexagon has 6 sides. What is the measure of one interior angle? What is the measure of all interior angles?

There are 6 triangles in a hexagon.

In an equilateral triangle the interior angles are 60 degrees.

You add them to get the interior angle of a hexagon.

60+60=120 degrees

One interior angle of a hexagon is 120 degrees.
To find them all out you multiply one angle by 6.

120(6)=720 degrees
All of the interior angles are 720 degrees.

Homework:
8.4 Text Book Work
-1-23 and 26-30
White Sheets
-All up to Age Problems