As a fraction it would be 388888/100000.
A= a+b/2 *h
6.5 = a+4/2 * 2
6.5/2 = a+4/2 *2/2
3.25 = a+4/2
3.25*2= a+4/2*2
6.5 = a+4
6.5-4 = a+4-4
2.5 = a
The missing measure is 2.5
Check
6.5= 2.5+4/2 *2
6.5= 2.5+2*2
6.5=2.5 + 4
6.5=6.5
it is called dun dun dun this Equivalent Ratio
Let the no of large frames bought be X
Then the no of smaller frames bought will be (17 - X )
Cost incurred = 14X + 5( 17 - X) = 130
14X + 85 - 5X = 130
9X = 45
X = 5
Answer 5 large frames and 12 small frames
Check
5X14 = 70
12X5 = 60
ADD = 130$
