Exercise 39 Page 238

To get the number of tiles Figure 12 has, substitute 12 for x in the given rule and simplify.

Kalil's guess is incorrect. Figure 12 has 102 tiles, not 108.

Practice makes perfect

Ms. Cai's class is studying a tile pattern that has the following rule. y = 10 x - 18 In this rule, the value of y is the number of tiles that Figure x of this pattern has. To find how many tiles will Figure 12 have, let's substitute 12 for x in this rule and simplify.

y = 10x - 18

Substitute

x= 12

y = 10( 12) - 18

Multiply

y = 120 - 18

SubTerm

Subtract term

y = 102

Figure 12 has 102 tiles. Therefore, Kalil's guess that Figure 12 has 108 tiles is incorrect.

Subchapter links

6.1.4 Using Rigid Transformations p.238

Exercise 39 Page 238

Hints

Check the answer

Practice exercises

Assess your skill