For the 2 given similar triangles the value of x is equal to 15cm.
We are given that 2 triangles are similar which means their sides are going to be equal.
For making calculation easy we can make name the 2 triangles as ABC and DEF
Where:
AB/ DE = BC/ EF = AC/ DF
We are given that AB = 18 cm BC = 9cm AC = xcm and in DE = 30cm DF = 25cm and EF = 15cm
So now we can substitute the values to find the measure of x which we labelled as AC.
18 /30 = 9/ 15 = x / 25
We can use :
9/15 = x / 25
Cross-multiplying :
15x = 225
x = 15
So the value of x = 15cm.