Question

making scaled copies

learning goal
lets draw scaled copies.

learning targets

• i can draw a scaled copy of a figure using a given scale factor.
• i know what operation to use on the side lengths of a figure to produce a scaled copy.

lesson terms

• corresponding
• scale factor
• scaled copy

warm up
more or less?
for each problem, select the answer from the two choices.

a. the value of ( 25 cdot (8.5) ) is:
more than 205
less than 205

b. the value of ( (9.93) cdot (0.984) ) is:
more than 10
less than 10

c. the value of ( (0.24) cdot (0.67) ) is:
more than 0.2
less than 0.2

Explanation:

Part a

Step1: Calculate \(25\times8.5\)

We know that \(25\times8 = 200\) and \(25\times0.5=12.5\). Then \(25\times8.5=25\times(8 + 0.5)=25\times8+25\times0.5 = 200 + 12.5=212.5\)

Step2: Compare with 205

Since \(212.5>205\), the value of \(25\times(8.5)\) is more than 205.

Step1: Analyze the product

We know that \(10\times1 = 10\), and \(9.93<10\), \(0.984<1\). When we multiply two numbers where one is less than 10 and the other is less than 1, the product will be less than \(10\times1 = 10\). Also, \(9.93\times0.984=(10 - 0.07)\times0.984=10\times0.984-0.07\times0.984 = 9.84-0.06888 = 9.77112\)

Step2: Compare with 10

Since \(9.77112<10\), the value of \((9.93)\times(0.984)\) is less than 10.

Step1: Calculate \(0.24\times0.67\)

\(0.24\times0.67 = 0.1608\)

Step2: Compare with 0.2

Since \(0.1608<0.2\), the value of \((0.24)\times(0.67)\) is less than 0.2.

Answer:

More than 205

Part b