It depends on what you are measuring the width of. Different units and different tools would be appropriate for a hair, a car or a galaxy.
If you don't have enough other information about the triangle to allow you to calculate the width, then you have to use a ruler or a tape measure.
inches
Millimeters or centimeters.
No, a ruler is used only to measure length, width or height. You must use a protractor in order to measure the degrees in an angle.
For a rectangle, length X width = area. Measure the length in cm. Measure the width in cm. Multiply the length X the width to get the area in cm2.
METERS!!!The unit of measurement you would use to measure the width of your classroom is meters.
centimeter?
Centimetre.
Parsecs
A tape measure.
a ruler
inches
Millimetres
You use a ruler or tape measure.
If you don't have enough other information about the triangle to allow you to calculate the width, then you have to use a ruler or a tape measure.
It is very hard to to measure the width. But for length you can use a tape measurer.
15 m