what is the size of all the planets in the solar system
I'm not sure if you mean the size of each planet or the size of what all of the planets together would be. I can do the first one. The second one is possible, but would involve a lot of math with some really big numbers.
The variable in your question is the word "size." What do you mean by size? Equatorial circumference or mass? I will give you both. I'm also going to give the measurements using the metric system, since that is the standard scientific unit system.
Mercury: Circumference = 15,329.1 km Mass = 3.3010 x 10^23 kg
Venus: Circumference = 38,024.6 km Mass 4.8673 x 1024 kg
Earth: Circumference = 40,030.2 km Mass = 5.9722 x 1024 kg
Mars: Circumference = 21,296.9 km Mass = 6.4169 x 1023 kg
Jupiter: Circumference = 439,263.8 km Mass = 1.8981 x 1027
Saturn: Circumference = 365,882.4 km Mass = 5.6832 x 1026 kg
Uranus: Circumference = 159,354.1 km Mass = 8.6810 x 1025 kg
Neptune: Circumference = 154,704.6 km Mass = 1.0241 x 1026 kg
Those are the 8 planets of our solar system. NASA has officially recognized 5 dwarf planets in addition to the 8 major planets listed above.