.Longitudinal-expansion-formula{width:128px; height:92px ;}
.veresk-bridge{width:200px; height:141px ;}
.expansion-problem{width:181px; height:111px ;}
.expansion-problem3{width:174px; height:65px ;}
.expansion-problem2{width:191px; height:165px ;}
.expansion-problem4{width:217px; height:172px ;}