Respuesta :

39 + 39 = 78

[tex] \dfrac{39}{78} = \dfrac{46}{x} [/tex]

Cross-multiply:
[tex]39x = 46 \times 78[/tex]

Evaluate the right hand side:
[tex]39x = 3588[/tex]

Divide both sides by 39:
[tex]x = 92[/tex]

92 because the bigger triangle is 2x the smaller, so 2(46)=92
hope this helps