Explain how an estimate you to place the decimal point when multiplying 3.9 * 5.3

3.9 × 5.3 = 20.67

Explanation:

given data

digit 1  =  3.9

digit 2 = 5.3

to find out

multiplying 3.9 * 5.3

solution

we know that 3.9 round about =  4

and 5.3 round about = 5

so 5 × 4  will be = 20

but here when we remove decimal

simple multiply it as

×

here 39 × 53 = 2067

and 10 × 10 = 100

so now we get

×  =  

put here again decimal point

3.9 × 5.3 = 20.67

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation: