1. 6.2 Proportions & Scale
HW pg. 367 #4­18 evens, 22
November 14, 2014
Bellwork
Solve the proportions.
1. 3 6 2. 1 3
8 x+1 15 s+8 36 4
3. Simplify the Ratio.
1200cm : 1.8m 20:3
4. Find the Geometric Mean of 42 & 12.
22.45
5. The area of a rectangle is 720 in 2
. If the ratio of the length to width is 5:4,
find the perimeter of the rectangle.
108 in.
­­ = ­­­ ­­­­ = ­­­

2. 6.2 Proportions & Scale
HW pg. 367 #4­18 evens, 22
November 14, 2014
6.2 Proportions
Reciprocal Property: If 2 ratios are =, then their reciprocals are =.
If a c, then b d
b d a c
Interchange the means: If a c, then a b
b d c d
Adding denominator to numerator: If a c, then a+b c+d
b d b d
­ = ­
­ = ­­ = ­
­ = ­ ­ = ­
­­­ = ­­­

3. 6.2 Proportions & Scale
HW pg. 367 #4­18 evens, 22
November 14, 2014

4. 6.2 Proportions & Scale
HW pg. 367 #4­18 evens, 22
November 14, 2014
Scale Drawing: same shape as object it represents
Scale: ratio that describes how the dimensions in the drawing are related to
the actual dimensions of the object.

5. 6.2 Proportions & Scale
HW pg. 367 #4­18 evens, 22
November 14, 2014

6. 6.2 Proportions & Scale
HW pg. 367 #4­18 evens, 22
November 14, 2014

7. 6.2 Proportions & Scale
HW pg. 367 #4­18 evens, 22
November 14, 2014
HW pg. 367 #4-18 evens & 22