General Idea:
When you have ratio a:b and b:c, to find the ratio of a:c, we need to multiply a:b with b:c. When multiplying fractions we need to multiply numerator with numerator and denominator with denominator. Then cancelling common terms we get the ratio a:c like shown below:
[tex] \frac{a}{b}\cdot \frac{b}{c} =\frac{a \cdot b}{b \cdot c} \\ Cancel \; common\;factor\;b\;in\;numerator\;and\;denominator\\ \\ \frac{a}{c} =a:c [/tex]
Applying the concept:
[tex] \frac{5}{7} \cdot \frac{4}{3} =\frac{5 \cdot 4}{7 \cdot 3} =\frac{20}{21} [/tex]
Conclusion:
Given that "The ratio of Alani's height is Baahir's height is 5:7, The ratio of Baahir's height to Conner's height is 4:3."
The ratio of Alani's height to Conner's height is 20:21
