...but the 32-bit CAN find the 64-bit JDK.
When I open Android Studio I receive
Error launching Android Studio No JVM installation found. Please
install a 64-bit JDK. If you already have a JDK installed, define a
...; C:\Program Files (x86)\Java\jdk1.8.0_91\bin
C:\Program Files (x86)\Java\jdk1.8.0_91
Android Studio 64-bit works on both 32-bit and 64-bit JDK. Depending on your JDK installation you select the launcher:
studio.exe is the 32-bit launcher. studio64.exe is the 64-bit launcher.
From your JDK path it's clear you have installed the 32-bit JDK. However, multiple JDKs can co-exist in one system so you can also install the 64-bit JDK if you wish.