4.1+Using+Similarity+to+Solve+a+Mystery

S.T 29/10/08 Block-C

=**4.1 & F.U.**=


 * No notes

The teacher's guides for Connected Mathematics measure 8.5" by 11". Below is a photograph of a middle school teacher holding a teacher's guide.

A. Use the photograph to figure out how tall the teacher is. Explain your procedure.**

Ans. Book's length in picture = 1.6 cm Actual length = 11" Teacher's height in picture = 11 cm 11 ÷ 1.6 = 6.875 ( ratio from book to teacher in the picture) 11" x 6.875 = 75.675 / 12 = 6.3 feet - 1.6/11 = 11 / x

I found the ratio in the picture and then replaced it with the real value which is the height of the book The scale factor from image to reality = 15.71, and if you round it up you get 16.


 * B. How do you think the police determined the height of the robber?**

Ans. The police probably found the robber's height by comparing the an object ( with known dimensions ) to the robber in the picture. I think they most probably used the method I used in part A.


 * Follow-Up**

Height of the book in the picture- 1.6 cm Height of the door in the picture- 5.6 cm 5.6 / 1.6 = x / 11" ( 11" is actual height of the book) 5.6 / 1.6- 5.6 times 11" = x x = height of the door = 3.5 times 11" = 38.5" = 3.2 ft
 * 1. Estimate the height of the door in the photograph**


 * 2. Do you think your estimate in question 1 is an underestimate or an over estimate? Why?**

I think the the estimate shown is an underestimate, as in the picture, the door is actually much behind the book. This makes the door appear smaller.