You would first look at the tens place numbers; 10 and 30. and add them together making 40. after that you'd take the ones places and add them together; 7 and 8. add those together and you'd get 15. to finish you just need to add the two numbers together 40 and 15.
16 cm - 2.5 cm = 13.5 cm, which is 1/4 of the diameter of the large gear. Take 13.5 cm * 4, and you have the diameter of the large gear, which is 54 cm.
Just simply collect like terms.
3x+4x+5+6
7x+11
Remember the notation..
When you have a triangle called ABD, the angles may be called in theses equivalent ways>
angle A is equivalent to ∠ DAB
angle B is equivalent to ∠ ABD
angle D is equivalen to ∠ BDA
Then given that the two triangles are congruent, you can say an
angle B = angle F = ∠ EFC
So the answer is the last option of the list.
