Daily Scribe:)

Today in class it was parent visitation day! We learned about the sun and it's shadows. We also learned how to tell the height of something by it's shadows. Here's some of the problems we did in class:

There's a clock tower in a local neighborhood that's height is unknown. There is also a stick that stands 3 meters high a little bit down the road. The shadow of the clock tower is 8 meters. The stick's shadow is 1.5 meters. How tall is the clock tower?

To find out how tall the clock tower is, the first thing you need to do is find two similar triangles. The first triangle consists of the clock tower, the shadow, and the imaginary line to close-off the shape. The second triangle is the stick, the shadow of the stick, and the imaginary line.There are two ways to complete the next step. You can find ratios such as: x/8 and 3/1.5. Or you can use Scale Factor. If you use ratios this is what you'll do: Divide 8 by 1.5 to get 5 1/3. Then multiply 3 by 5 1/3 to get about 16. (The fractions and decimals will make the numbers funny so try to round up if your answer still seems accurate.) Therefore, the length of the clock tower is 16 feet!

If you do it by scale factor this is what you can do: divide 3 by 1.5 to get 2 .Then, multiply 8 by 2 to get 16. Therefore, the length of the clock tower is 16 meters!

No matter which way you do it you will always get the same answer!

Another problem we did was using a mirror.

Jim is standing in a street with a mirror laid on the ground 100 cm. in front of him. 450 cm. past the mirror is a traffic light. From the ground to Jim's eyes is 150 cm. How tall is the traffic light? I will solve this problem using ratios. x/450 and 150/100. 450 divided by 100 equals 4.5. 150 times 4.5 equals 675. Therefore, the traffic light is 675 cm.

These problems are really simple if you break them down. Find the two similar triangles, find the ratios or scale factor and you have your missing length!

Somethings to remember when you're doing these problems are:

The suns rays are always parallel.

Always look at the unit because sometimes not all of the lenghts will be in the same unit. And lastly,

remember to check your work!

There will be a chapter test on Wednesday, so study up!