Point C is taken inside the segment AB, so AC: BC = 3: 7 AB = 56 Find BC.

Let us determine how many identical parts the segment AB can be divided into, when from the condition of the task we know that AC refers to BC as 3 to 7:

3 + 7 = 10.

Let us determine how many centimeters the length of one such part will equal, when from the condition of the task we know that the length of the segment AB is equal to fifty-six centimeters:

56: 10 = 5.6.

Let’s determine how many centimeters the length of the BC segment will be equal to:

7 * 5.6 = 39.2.

Answer: Under such conditions, the length of the aircraft is 39.2 cm.