Find the length of the rectangle if x= 10. And find the perimeter if x=10

PLEASE HELP .

The sixth grade art students are making a mosaic using tiles in the shape of right triangles.each tile has leg measures of 3 centimeters and 5 centimeters.i f there are 200 tiles in the mosaic what is the area of the mosaic.

What percent of the circle below is shaded?

15 there is a line that includes the point 0,10 and has a slope of 7/4. what is it’s equation in slope intercept form