what is 21C in fahrenheit
21Â°C = 69.8Â°F. Use the formula F = 9/5C + 32. To convert from Celsius to Fahrenheit, multiply the number by 9, divide by 5, and add 32. In this instance, 21 x 9 = 189 / 5 = 37.8 + 32 = 69.8. Therefore, 21 degrees Celsius is equal to 69.8 degrees Fahrenheit.se the formula F = 9/5C + 32. To convert from Celsius to Fahrenheit, multiply the number by 9, divide by 5, and add 32.