What's the opposite of -3.9

this webesite is helpful

Step-by-step explanation:

https://www.math.net/opposite-of-a-number

positive 3.9

negative is the opposite of positive

positive it the opposite of negative

a reflection across the x-axis , followed by the by a reflection across the y-axis , and then a scale dilation of 0.5 .

the correct option is 2.

step-by-step explanation:

according to the given information triangle abc is a right angle triangle with right angle at a. segment ab is 5 and segment ac is 7. point d is on segment bc and angles adb and adc are right angles.

it is given that triangles abd, cad, and cba are similar.

two triangles are similar if their corresponding sides are proportional.

in triangle cba, using pythagoras theorem

                      )

triangle abd and cba are similar,

                            (2)

triangle cad and cba are similar,

                      )

using (1), (2) and (3), we get

hence proved.

therefore option 2 is correct.