Question

which of the following has the proportions would allow us to figure out how many units 80 cm is? hint: video timestamp is 1:50 for this concept.
a
\\(\frac{15cm}{3units} = \frac{x}{80units}\\)
b
\\(\frac{15cm}{3units} = \frac{80cm}{x}\\)
c
\\(\frac{3cm}{15units} = \frac{x}{80cm}\\)

Explanation:

Step1: Understand the Proportion Concept

We need to relate centimeters to units. Let's assume the ratio of cm to units is constant. So, if we have a known ratio of cm to units, we can set up a proportion for 80 cm.

Step2: Analyze Each Option

• Option a: $\frac{15cm}{3units} = \frac{x}{80units}$ – Here, the right side has units in the denominator and we're solving for x (cm?), which doesn't match the goal of finding units for 80 cm.
• Option b: $\frac{15cm}{3units} = \frac{80cm}{x}$ – The left side is cm per unit, so the right side should also be cm per unit. Solving for x (units) here makes sense, as we want to find how many units 80 cm is.
• Option c: $\frac{3cm}{15units} = \frac{x}{80cm}$ – The units and cm are mixed incorrectly, and the ratio setup is wrong for finding units of 80 cm.

Answer:

b. $\boldsymbol{\frac{15cm}{3units} = \frac{80cm}{x}}$