Anja is creating a triangle using three straws. the two shorter straws have lengths of 20 cm and 21 cm. how long, in centimeters, should the third straw be for anja to create a right triangle?

Length of third straw must be:

29 cm

Step-by-step explanation:

We know that the longest side in a right angled triangle is its hypotenuse.

Pythagoras theorem says that:

hypotenuse²=base²+perpendicular²

Here, we are given base and perpendicular and we have to find the length of the hypotenuse.

hypotenuse²=20²+21²

                   =400+441

                  =841

hypotenuse=√(841)

                  = 29 cm

Hence, length of the third straw must be:

29 cm

the largest number of the four options is 1.8 x 10-2

you have it in scientific notation.

1.80 x 10-6   = 0.00000180

1.80 x 10-4   = 0.000180 (bigger, or "less small", than the former one)

so

1.8 x 10-2       = 0.0180. as you see. the "less small", or the biggest one of them all.

as you have negative exponent, it means you are dividing 1.8 by 100 (i.e. moving the dot towards left, two times).

if you had positive exponent for the scientific notation, power of tenths, you would be multiplying times 100 (moving the dot towards right) as below:

1.8 x (10)2 = 180

so. if you have negative exponent in scientific notation, move the dot toward left. if it is positive, toward right as many times the exponent tells you.

i think the correct option is the second option.