If you look at the model RM is the same length as PM. PM=10 so RM=10.
Row A: x = 3
y = 2x - 3
y = 2(3) - 3 = 3 This is correct
Row B: x = 5
y = 2x - 3
y = 2(5) - 3 = 7 This is correct
Row C: x = 7
y = 2x - 3
y = 2(7) - 3 = 11 this is correct
Row D: x = 10
y = 2x - 3
y = 2(10) - 3 = 17 THIS IS INCORRECT, SO ROW D
X=46.2
_____________________________
99.2 + 62 = 161.2
180 -161.2 = 19.8
19.8 + 112 = 131.8
180 - 131.8 = 48.2
48.2 - 2 = 46.2
∆PQR and ∆SQT are similar, so corresponding sides occur in fixed ratios with one another. This means
SQ / PQ = ST / PR
Solve for x :
8 / ((x + 5) + 8) = (x - 9) / 21
8 / (x + 13) = (x - 9) / 21
168 = (x - 9) (x + 13)
168 = x² + 4x - 117
x² + 4x - 285 = 0
(x + 19) (x - 15) = 0
⇒ x = -19 or x = 15
But x can't be smaller than 9, otherwise ST = x - 9 would be a negative length. So x = 15.
Answer: This is an example of Centration.
Centration refers to the tendency to focus on only one aspect of a situation, problem or object. For example: a child may complain that there is little ice cream left in a big bowl. The child will be satisfied if the ice cream is transferred to a little bowl, even though nothing is added, because he only considers how full the bowl appears to be.
