What is tan(40)=x/12? And shouldn't the answer be one or two numbers shy of 12?

If it is 40° then:  x = 12*tan(40°) = 12*0.8391 = 10.0692

Solution

1

Multiply both sides by 1212

tan40×12=xtan⁡40×12=x

2

Switch sides

x=tan40×12x=tan⁡40×12

Done

Decimal Form: -13.4066

Check Answer ▲

tan40=x12tan⁡40=x12

1

Let x=tan40×12x=tan⁡40×12

tan40=tan40×1212tan⁡40=tan⁡40×1212

2

Cancel 1212

tan40=tan40tan⁡40=tan⁡40

Done