What are the width and length of a lawn tennis court for singles matches?

Under the rules of the International Tennis Federation (ITF), a singles tennis court is 78 feet (23.77 m) long and 27 feet (8.23 m) wide.

Measurements of a tennis court:

• Length: 78 feet (23.77 m) for both singles and doubles.
• Width: 27 feet (8.23 m) for singles and 36 feet (10.97 m) for doubles.
• The extra 4.5 feet on each side for doubles are called the "tramlines" or "alleys".
• The service line is 21 feet (6.40 m) from the net on each side.
• The centre service line divides the service area into two service boxes.
• Net height: 3 feet (0.914 m) at the centre and 3.5 feet (1.07 m) at the posts.
• The baseline is the back line at each end, with a centre mark.

Court surfaces in the Grand Slams:

• Australian Open: hard court (Melbourne).
• French Open: clay (Roland-Garros, Paris).
• Wimbledon: grass (London).
• US Open: hard court (Flushing Meadows, New York).

Other tennis equipment rules:

• The racket must not be longer than 29 inches (73.7 cm) or wider than 12.5 inches.
• The ball is yellow (optic yellow) or white and weighs 56.0-59.4 g.
• Lawn tennis was developed in England in the 1870s; Major Walter Wingfield patented a version called "Sphairistike" in 1874.
• The ITF, founded in 1913, is headquartered in London.

Why not the other options?

• ✗36 feet and 78 feet are the dimensions of a doubles court.
• ✗20 feet and 44 feet are roughly the dimensions of a doubles badminton court (6.10 m x 13.40 m).
• ✗30 feet and 90 feet are not tennis court measurements.