Question

4
1.7 cm
4 cm
9.3 cm
0.4 cm
0.93 cm
r = ______ cm

Explanation:

Step1: Assume the two trapezoids are similar.

If two polygons are similar, the ratios of their corresponding - side lengths are equal.

Step2: Set up the proportion.

The ratio of the corresponding non - parallel sides gives us the scale factor. Let's use the ratio of the non - parallel sides to find the ratio of the parallel sides. The ratio of the non - parallel sides is $\frac{0.4}{4}=0.1$.
The ratio of the upper - base lengths should be the same as the ratio of the non - parallel sides. Let the upper - base of the first trapezoid be $a = 1.7$ cm and the upper - base of the second trapezoid be $r$, and the ratio of the non - parallel sides $k=\frac{0.4}{4}$. Then $\frac{r}{1.7}=\frac{0.4}{4}$.

Step3: Solve for $r$.

Cross - multiply: $4r=1.7\times0.4$. Then $4r = 0.68$. Divide both sides by 4: $r=\frac{0.68}{4}=0.17$ cm.

Answer:

$0.17$