Answer:
according to basic proportionality theorem
[tex]\qquad\sf {:}\longrightarrow 25/35=x/63 [/tex]
[tex]\qquad\sf {:}\longrightarrow 5/7=x/63[/tex]
[tex]\qquad\sf {:}\longrightarrow 7x=63×5=315 [/tex]
[tex]\qquad\sf {:}\longrightarrow x=315/7=45 [/tex]
