The micrometre (International spelling as used by the International Bureau of Weights and Measures;[1] SI symbol: μm) or micrometer (American spelling), alsocommonly known as a micron, is an SI derived unit of length equaling 1×10−6 of ametre (SI standard prefix "micro-" = 10−6); that is, one millionth of a metre (or one thousandth of a millimetre, 0.001 mm, or about 0.000039 inch).[1] The symbol μm is sometimes rendered as um if the symbol μ cannot be used, or if the writer is not aware of the distinction.<span>[citation needed]</span>
The micrometre is a common unit of measurement for wavelengths of infrared radiation as well as sizes of biological cells and bacteria and is also commonly used in plastics manufacturing.[1] Micrometres are the standard for grading wool by the diameter of the fibres; wool finer than 25 μm can be used for garments, while coarser grades are used for outerwear, rugs, and carpets.[2] The width of a single human hair ranges from approximately 10 to 200 μm. The first and longest human chromosome is 10μm in length.
Contents <span> [hide] </span><span><span>1Examples</span><span>2SI standardization</span><span>3Symbol</span><span>4See also</span><span>5<span>Notes and references</span></span></span>
Answer: 306.9
Step-by-step explanation: 3.1 x 11 = 34.1 x 9 = 306.9
In ΔABC,
tanA = a/b
∴ a = b×tanA = 12×1/√3 = 6.928 ~ 6.93 m
Answer:
Step-by-step explanation:
Since the sample size is quite large, we can use the z-distribution.
The margin of error is given by
Where n is the sample size, s is the sample standard deviation and 
is the z-score corresponding to a 90% confidence level.
The z-score corresponding to a 90% confidence level is
Significance level = α = 1 - 0.90= 0.10/2 = 0.05
From the z-table at α = 0.05
z-score = 1.645
Therefore, the margin of error is 0.776.
