Abstract: A tape measure has a first scale on one edge of the blade and a second scale on the other edge blade where the second scale is marked in units of length which are equal to the units of the first scale multiplied by the square root of 2. A method to check a right angle measures from a corner to a distal end of a first line using the units of the first scale, measures along a second line an equal length in the first units from the corner and marking a point, by measuring from the distal end to the point using the second scale and by adjusting an angle between the first and second lines at the corner until the distance between the distal end and the point is equal to the length of the first line when measured on the second scale.

Abstract: A tape measure has a first scale on one edge of the blade and a second scale on the other edge blade where the second scale is marked in units of length which are equal to the units of the first scale multiplied by the square root of 2. A method to check a right angle measures from a corner to a distal end of a first line using the units of the first scale, measures along a second line an equal length in the first units from the corner and marking a point, by measuring from the distal end to the point using the second scale and by adjusting an angle between the first and second lines at the corner until the distance between the distal end and the point is equal to the length of the first line when measured on the second scale.

Abstract: A reel dedicated to the layout of a baseball diamond includes a tape with an inner end reeled onto a reel body and an outer end attached to the reel body to form a loop of the tape. The loop has a length 2x+.sqroot.2x and has a first base marking at a distance x from the outer end, a second base marking at a distance 2x from the outer end, a third base marking at a distance x+.sqroot.2x from the outer end and a pitcher's plate marking at a distance of y from the inner end. x is equal to the required distance between bases. y is equal to the distance of the pitcher's plate from home base. The loop is pulled out into a first triangle from first base to second base and back to home plate and then in a second triangle from home plate to first base and to third base to accurately lay out the positions of pegs.