PowerShell, 45(削除) 45 (削除ここまで) 42 bytes
param($a)65..$a|%$args[0]|%{" "*$i+++"$([char]$_) "*$i}
Takes input as a literal char, then loops up through the capitals to that point, each iteration prepending the appropriate number of spaces and then the char\space hybrid.
Saved 3 bytes thanks to TessellatingHeckler.
PowerShell, 45 bytes
param($a)65..$a|%{" "*$i+++"$([char]$_) "*$i}
Takes input as a literal char, then loops up through the capitals to that point, each iteration prepending the appropriate number of spaces and then the char\space hybrid.
PowerShell, (削除) 45 (削除ここまで) 42 bytes
65..$args[0]|%{" "*$i+++"$([char]$_) "*$i}
Takes input as a literal char, then loops up through the capitals to that point, each iteration prepending the appropriate number of spaces and then the char\space hybrid.
Saved 3 bytes thanks to TessellatingHeckler.
PowerShell, 45 bytes
param($a)65..$a|%{" "*$i+++"$([char]$_) "*$i}
Takes input as a literal char, then loops up through the capitals to that point, each iteration prepending the appropriate number of spaces and then the char\space hybrid.